[INFO] cloning repository https://github.com/BarkSanson/bark-dns-resolver
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/BarkSanson/bark-dns-resolver" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBarkSanson%2Fbark-dns-resolver", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBarkSanson%2Fbark-dns-resolver'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8e75770cb12c19a5dd8bd8d6afb9f4d794e11ae8
[INFO] checking BarkSanson/bark-dns-resolver against try#44f3504e96c944ae54fc72b5f5008f53f7eda001 for pr-136776
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBarkSanson%2Fbark-dns-resolver" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/BarkSanson/bark-dns-resolver on toolchain 44f3504e96c944ae54fc72b5f5008f53f7eda001
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/BarkSanson/bark-dns-resolver
[INFO] finished tweaking git repo https://github.com/BarkSanson/bark-dns-resolver
[INFO] tweaked toml for git repo https://github.com/BarkSanson/bark-dns-resolver written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/BarkSanson/bark-dns-resolver already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3959728d45483eb673ba100a951a6b9f5012970368db2a9e08e0ac9b67c8a5ad" "/opt/rustwide/cargo-home/bin/cargo" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1a1486456b1c0a9ed8d8bd2883ebcd1d1a2fc25910e4495179d0ba5f2126c570
[INFO] running `Command { std: "docker" "start" "-a" "1a1486456b1c0a9ed8d8bd2883ebcd1d1a2fc25910e4495179d0ba5f2126c570", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1a1486456b1c0a9ed8d8bd2883ebcd1d1a2fc25910e4495179d0ba5f2126c570", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1a1486456b1c0a9ed8d8bd2883ebcd1d1a2fc25910e4495179d0ba5f2126c570", kill_on_drop: false }`
[INFO] [stdout] 1a1486456b1c0a9ed8d8bd2883ebcd1d1a2fc25910e4495179d0ba5f2126c570
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3959728d45483eb673ba100a951a6b9f5012970368db2a9e08e0ac9b67c8a5ad" "/opt/rustwide/cargo-home/bin/cargo" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b621bf281ae1e36b84c5d90a4cc02ea2093bd27a33913b14b5f088c578093fea
[INFO] running `Command { std: "docker" "start" "-a" "b621bf281ae1e36b84c5d90a4cc02ea2093bd27a33913b14b5f088c578093fea", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.155
[INFO] [stderr]     Checking regex-syntax v0.8.4
[INFO] [stderr]     Checking getrandom v0.2.15
[INFO] [stderr]     Checking rand_core v0.6.4
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking rand v0.8.5
[INFO] [stderr]     Checking regex-automata v0.4.7
[INFO] [stderr]     Checking regex v1.10.5
[INFO] [stderr]     Checking bark-dns-resolver v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::ptr::read`
[INFO] [stdout]  --> src/msg.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::ptr::read;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `AResourceRecord` and `CNameResourceRecord`
[INFO] [stdout]  --> src/msg.rs:8:30
[INFO] [stdout]   |
[INFO] [stdout] 8 | use crate::resource_record::{AResourceRecord, Class, CNameResourceRecord, ResourceRecord, ResourceRecordFactory, ResourceRecordHeader, Ty...
[INFO] [stdout]   |                              ^^^^^^^^^^^^^^^         ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::Bytes`
[INFO] [stdout]  --> src/resource_record.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::io::Bytes;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ptr::read`
[INFO] [stdout]  --> src/msg.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::ptr::read;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `AResourceRecord` and `CNameResourceRecord`
[INFO] [stdout]  --> src/msg.rs:8:30
[INFO] [stdout]   |
[INFO] [stdout] 8 | use crate::resource_record::{AResourceRecord, Class, CNameResourceRecord, ResourceRecord, ResourceRecordFactory, ResourceRecordHeader, Ty...
[INFO] [stdout]   |                              ^^^^^^^^^^^^^^^         ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::Bytes`
[INFO] [stdout]  --> src/resource_record.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::io::Bytes;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `is_compression_byte` is never read
[INFO] [stdout]   --> src/domain_name.rs:53:17
[INFO] [stdout]    |
[INFO] [stdout] 53 |         let mut is_compression_byte = false;
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `is_compression_byte` is never read
[INFO] [stdout]   --> src/domain_name.rs:53:17
[INFO] [stdout]    |
[INFO] [stdout] 53 |         let mut is_compression_byte = false;
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `msg`
[INFO] [stdout]   --> src/requester.rs:56:13
[INFO] [stdout]    |
[INFO] [stdout] 56 |         let msg = DNSMessage::deserialize(buf, 0)?;
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_msg`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/msg.rs:224:8
[INFO] [stdout]     |
[INFO] [stdout] 223 | impl Question {
[INFO] [stdout]     | ------------- associated function in this implementation
[INFO] [stdout] 224 |     fn new(qname: DomainName, qtype: Type, qclass: Class) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `msg`
[INFO] [stdout]   --> src/requester.rs:56:13
[INFO] [stdout]    |
[INFO] [stdout] 56 |         let msg = DNSMessage::deserialize(buf, 0)?;
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_msg`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `answers`, `authorities`, and `additional` are never read
[INFO] [stdout]    --> src/msg.rs:293:5
[INFO] [stdout]     |
[INFO] [stdout] 290 | pub(crate) struct DNSMessage {
[INFO] [stdout]     |                   ---------- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 293 |     answers: Option<Vec<Box<dyn ResourceRecord>>>,
[INFO] [stdout]     |     ^^^^^^^
[INFO] [stdout] 294 |     authorities: Option<Vec<Box<dyn ResourceRecord>>>,
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout] 295 |     additional: Option<Vec<Box<dyn ResourceRecord>>>
[INFO] [stdout]     |     ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new_from_components` is never used
[INFO] [stdout]    --> src/msg.rs:299:19
[INFO] [stdout]     |
[INFO] [stdout] 298 | impl DNSMessage {
[INFO] [stdout]     | --------------- associated function in this implementation
[INFO] [stdout] 299 |     pub(crate) fn new_from_components(
[INFO] [stdout]     |                   ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `ResponseData` is never used
[INFO] [stdout]   --> src/resource_record.rs:52:17
[INFO] [stdout]    |
[INFO] [stdout] 52 | pub(crate) enum ResponseData {
[INFO] [stdout]    |                 ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `name`, `rr_class`, `ttl`, and `rdlength` are never read
[INFO] [stdout]   --> src/resource_record.rs:67:5
[INFO] [stdout]    |
[INFO] [stdout] 66 | pub struct ResourceRecordHeader {
[INFO] [stdout]    |            -------------------- fields in this struct
[INFO] [stdout] 67 |     name: DomainName,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 68 |     rr_type: Type,
[INFO] [stdout] 69 |     rr_class: Class,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 70 |     ttl: i32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 71 |     rdlength: u16,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/resource_record.rs:75:19
[INFO] [stdout]    |
[INFO] [stdout] 74 | impl ResourceRecordHeader {
[INFO] [stdout]    | ------------------------- associated function in this implementation
[INFO] [stdout] 75 |     pub(crate) fn new(
[INFO] [stdout]    |                   ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `serialize` is never used
[INFO] [stdout]    --> src/resource_record.rs:149:8
[INFO] [stdout]     |
[INFO] [stdout] 146 | pub(crate) trait ResourceRecord {
[INFO] [stdout]     |                  -------------- associated function in this trait
[INFO] [stdout] ...
[INFO] [stdout] 149 |     fn serialize() -> Vec<u8> where Self: Sized;
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `header` and `ip` are never read
[INFO] [stdout]    --> src/resource_record.rs:153:5
[INFO] [stdout]     |
[INFO] [stdout] 152 | pub(crate) struct AResourceRecord {
[INFO] [stdout]     |                   --------------- fields in this struct
[INFO] [stdout] 153 |     header: ResourceRecordHeader,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 154 |     ip: Ipv4Addr
[INFO] [stdout]     |     ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/resource_record.rs:158:8
[INFO] [stdout]     |
[INFO] [stdout] 157 | impl AResourceRecord {
[INFO] [stdout]     | -------------------- associated function in this implementation
[INFO] [stdout] 158 |     fn new(header: ResourceRecordHeader, ip: Ipv4Addr) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `header` and `cname` are never read
[INFO] [stdout]    --> src/resource_record.rs:180:5
[INFO] [stdout]     |
[INFO] [stdout] 179 | pub(crate) struct CNameResourceRecord {
[INFO] [stdout]     |                   ------------------- fields in this struct
[INFO] [stdout] 180 |     header: ResourceRecordHeader,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 181 |     cname: DomainName
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `is_valid` is never used
[INFO] [stdout]   --> src/domain_name.rs:14:8
[INFO] [stdout]    |
[INFO] [stdout] 7  | impl DomainName {
[INFO] [stdout]    | --------------- associated function in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 14 |     fn is_valid(domain_name: String) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/msg.rs:224:8
[INFO] [stdout]     |
[INFO] [stdout] 223 | impl Question {
[INFO] [stdout]     | ------------- associated function in this implementation
[INFO] [stdout] 224 |     fn new(qname: DomainName, qtype: Type, qclass: Class) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `answers`, `authorities`, and `additional` are never read
[INFO] [stdout]    --> src/msg.rs:293:5
[INFO] [stdout]     |
[INFO] [stdout] 290 | pub(crate) struct DNSMessage {
[INFO] [stdout]     |                   ---------- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 293 |     answers: Option<Vec<Box<dyn ResourceRecord>>>,
[INFO] [stdout]     |     ^^^^^^^
[INFO] [stdout] 294 |     authorities: Option<Vec<Box<dyn ResourceRecord>>>,
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout] 295 |     additional: Option<Vec<Box<dyn ResourceRecord>>>
[INFO] [stdout]     |     ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new_from_components` is never used
[INFO] [stdout]    --> src/msg.rs:299:19
[INFO] [stdout]     |
[INFO] [stdout] 298 | impl DNSMessage {
[INFO] [stdout]     | --------------- associated function in this implementation
[INFO] [stdout] 299 |     pub(crate) fn new_from_components(
[INFO] [stdout]     |                   ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `ResponseData` is never used
[INFO] [stdout]   --> src/resource_record.rs:52:17
[INFO] [stdout]    |
[INFO] [stdout] 52 | pub(crate) enum ResponseData {
[INFO] [stdout]    |                 ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `name`, `rr_class`, `ttl`, and `rdlength` are never read
[INFO] [stdout]   --> src/resource_record.rs:67:5
[INFO] [stdout]    |
[INFO] [stdout] 66 | pub struct ResourceRecordHeader {
[INFO] [stdout]    |            -------------------- fields in this struct
[INFO] [stdout] 67 |     name: DomainName,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 68 |     rr_type: Type,
[INFO] [stdout] 69 |     rr_class: Class,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 70 |     ttl: i32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 71 |     rdlength: u16,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/resource_record.rs:75:19
[INFO] [stdout]    |
[INFO] [stdout] 74 | impl ResourceRecordHeader {
[INFO] [stdout]    | ------------------------- associated function in this implementation
[INFO] [stdout] 75 |     pub(crate) fn new(
[INFO] [stdout]    |                   ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `serialize` is never used
[INFO] [stdout]    --> src/resource_record.rs:149:8
[INFO] [stdout]     |
[INFO] [stdout] 146 | pub(crate) trait ResourceRecord {
[INFO] [stdout]     |                  -------------- associated function in this trait
[INFO] [stdout] ...
[INFO] [stdout] 149 |     fn serialize() -> Vec<u8> where Self: Sized;
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `header` and `ip` are never read
[INFO] [stdout]    --> src/resource_record.rs:153:5
[INFO] [stdout]     |
[INFO] [stdout] 152 | pub(crate) struct AResourceRecord {
[INFO] [stdout]     |                   --------------- fields in this struct
[INFO] [stdout] 153 |     header: ResourceRecordHeader,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 154 |     ip: Ipv4Addr
[INFO] [stdout]     |     ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/resource_record.rs:158:8
[INFO] [stdout]     |
[INFO] [stdout] 157 | impl AResourceRecord {
[INFO] [stdout]     | -------------------- associated function in this implementation
[INFO] [stdout] 158 |     fn new(header: ResourceRecordHeader, ip: Ipv4Addr) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `header` and `cname` are never read
[INFO] [stdout]    --> src/resource_record.rs:180:5
[INFO] [stdout]     |
[INFO] [stdout] 179 | pub(crate) struct CNameResourceRecord {
[INFO] [stdout]     |                   ------------------- fields in this struct
[INFO] [stdout] 180 |     header: ResourceRecordHeader,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 181 |     cname: DomainName
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `is_valid` is never used
[INFO] [stdout]   --> src/domain_name.rs:14:8
[INFO] [stdout]    |
[INFO] [stdout] 7  | impl DomainName {
[INFO] [stdout]    | --------------- associated function in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 14 |     fn is_valid(domain_name: String) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     Requester::get_ipv4_address("gmail.google.com");
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let _ = Requester::get_ipv4_address("gmail.google.com");
[INFO] [stdout]   |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     Requester::get_ipv4_address("gmail.google.com");
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let _ = Requester::get_ipv4_address("gmail.google.com");
[INFO] [stdout]   |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 5.51s
[INFO] running `Command { std: "docker" "inspect" "b621bf281ae1e36b84c5d90a4cc02ea2093bd27a33913b14b5f088c578093fea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b621bf281ae1e36b84c5d90a4cc02ea2093bd27a33913b14b5f088c578093fea", kill_on_drop: false }`
[INFO] [stdout] b621bf281ae1e36b84c5d90a4cc02ea2093bd27a33913b14b5f088c578093fea
