[INFO] fetching crate erkpht-tower 0.3.2...
[INFO] testing erkpht-tower-0.3.2 against beta-2026-03-05 for beta-1.95-1
[INFO] extracting crate erkpht-tower 0.3.2 into /workspace/builds/worker-7-tc2/source
[INFO] started tweaking crates.io crate erkpht-tower 0.3.2
[INFO] finished tweaking crates.io crate erkpht-tower 0.3.2
[INFO] tweaked toml for crates.io crate erkpht-tower 0.3.2 written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate erkpht-tower 0.3.2 on toolchain beta-2026-03-05
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-03-05" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-03-05" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 102 packages to latest compatible versions
[INFO] [stderr]       Adding hdrhistogram v6.3.4 (available: v7.5.4)
[INFO] [stderr]       Adding indexmap v1.9.3 (available: v2.13.0)
[INFO] [stderr]       Adding pin-project v0.4.30 (available: v1.1.11)
[INFO] [stderr]       Adding quickcheck v0.6.2 (available: v1.1.0)
[INFO] [stderr]       Adding rand v0.7.3 (available: v0.10.0)
[INFO] [stderr]       Adding tokio v0.2.25 (available: v1.50.0)
[INFO] [stderr]       Adding tokio-test v0.2.1 (available: v0.4.5)
[INFO] [stderr]       Adding tower-test v0.3.0 (available: v0.4.0)
[INFO] [stderr]       Adding tracing-subscriber v0.1.6 (available: v0.3.22)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-03-05" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-03-05" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e3af05e162df0cf0d806d2884b9692bcf9cfcc42414c2614e255b6e9c795e5c0
[INFO] running `Command { std: "docker" "start" "-a" "e3af05e162df0cf0d806d2884b9692bcf9cfcc42414c2614e255b6e9c795e5c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e3af05e162df0cf0d806d2884b9692bcf9cfcc42414c2614e255b6e9c795e5c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e3af05e162df0cf0d806d2884b9692bcf9cfcc42414c2614e255b6e9c795e5c0", kill_on_drop: false }`
[INFO] [stdout] e3af05e162df0cf0d806d2884b9692bcf9cfcc42414c2614e255b6e9c795e5c0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-03-05" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a81d7d2255504eef85c491a0a4d87f9272176dce917f3b879f1ee45c0e3ed126
[INFO] running `Command { std: "docker" "start" "-a" "a81d7d2255504eef85c491a0a4d87f9272176dce917f3b879f1ee45c0e3ed126", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling pin-project-internal v0.4.30
[INFO] [stderr]    Compiling tracing-attributes v0.1.31
[INFO] [stderr]    Compiling tracing v0.1.44
[INFO] [stderr]    Compiling pin-project v0.4.30
[INFO] [stderr]    Compiling erkpht-tower v0.3.2 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.91s
[INFO] running `Command { std: "docker" "inspect" "a81d7d2255504eef85c491a0a4d87f9272176dce917f3b879f1ee45c0e3ed126", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a81d7d2255504eef85c491a0a4d87f9272176dce917f3b879f1ee45c0e3ed126", kill_on_drop: false }`
[INFO] [stdout] a81d7d2255504eef85c491a0a4d87f9272176dce917f3b879f1ee45c0e3ed126
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-03-05" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 52fa62a37ca842aa52e546628fa9118e2ebdbdfc3c9b4c5e74d6e59832a720ca
[INFO] running `Command { std: "docker" "start" "-a" "52fa62a37ca842aa52e546628fa9118e2ebdbdfc3c9b4c5e74d6e59832a720ca", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.8.0
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling version_check v0.1.5
[INFO] [stderr]    Compiling crc32fast v1.5.0
[INFO] [stderr]    Compiling simd-adler32 v0.3.8
[INFO] [stderr]    Compiling bytes v0.5.6
[INFO] [stderr]    Compiling pin-project-lite v0.1.12
[INFO] [stderr]    Compiling crossbeam-utils v0.6.6
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]    Compiling iana-time-zone v0.1.65
[INFO] [stderr]    Compiling futures-task v0.3.32
[INFO] [stderr]    Compiling stable_deref_trait v1.2.1
[INFO] [stderr]    Compiling base64 v0.10.1
[INFO] [stderr]    Compiling matchers v0.0.1
[INFO] [stderr]    Compiling tracing-log v0.1.4
[INFO] [stderr]    Compiling quickcheck v0.6.2
[INFO] [stderr]    Compiling futures-util v0.3.32
[INFO] [stderr]    Compiling miniz_oxide v0.8.9
[INFO] [stderr]    Compiling owning_ref v0.4.1
[INFO] [stderr]    Compiling nom v4.2.3
[INFO] [stderr]    Compiling chrono v0.4.44
[INFO] [stderr]    Compiling crossbeam-channel v0.3.9
[INFO] [stderr]    Compiling smallvec v0.6.14
[INFO] [stderr]    Compiling tokio v0.2.25
[INFO] [stderr]    Compiling flate2 v1.1.9
[INFO] [stderr]    Compiling aho-corasick v1.1.4
[INFO] [stderr]    Compiling hdrhistogram v6.3.4
[INFO] [stderr]    Compiling regex-automata v0.4.14
[INFO] [stderr]    Compiling tokio-test v0.2.1
[INFO] [stderr]    Compiling tower-test v0.3.0
[INFO] [stderr]    Compiling regex v1.12.3
[INFO] [stderr]    Compiling tracing-subscriber v0.1.6
[INFO] [stderr]    Compiling erkpht-tower v0.3.2 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 15.09s
[INFO] [stderr] warning: the following packages contain code that will be rejected by a future version of Rust: hdrhistogram v6.3.4, nom v4.2.3
[INFO] [stderr] note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 1`
[INFO] running `Command { std: "docker" "inspect" "52fa62a37ca842aa52e546628fa9118e2ebdbdfc3c9b4c5e74d6e59832a720ca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "52fa62a37ca842aa52e546628fa9118e2ebdbdfc3c9b4c5e74d6e59832a720ca", kill_on_drop: false }`
[INFO] [stdout] 52fa62a37ca842aa52e546628fa9118e2ebdbdfc3c9b4c5e74d6e59832a720ca
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-03-05" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 09c4601ba6cc94ca6961dbcafcc1fecfa86ddf5e06e59f82e243348229887719
[INFO] running `Command { std: "docker" "start" "-a" "09c4601ba6cc94ca6961dbcafcc1fecfa86ddf5e06e59f82e243348229887719", kill_on_drop: false }`
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.12s
[INFO] [stderr] warning: the following packages contain code that will be rejected by a future version of Rust: hdrhistogram v6.3.4, nom v4.2.3
[INFO] [stderr] note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 1`
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/erkpht_tower-d960c720840bec8d)
[INFO] [stdout] 
[INFO] [stderr]      Running tests/balance/main.rs (/opt/rustwide/target/debug/deps/balance-b4ca42b2d476258b)
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]      Running tests/buffer/main.rs (/opt/rustwide/target/debug/deps/buffer-79612d2a3accfd21)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]      Running tests/builder.rs (/opt/rustwide/target/debug/deps/builder-1f12fc651ada7598)
[INFO] [stdout] 
[INFO] [stderr]      Running tests/filter/main.rs (/opt/rustwide/target/debug/deps/filter-7a2ea52a405425c0)
[INFO] [stdout] running 0 tests
[INFO] [stderr]      Running tests/hedge/main.rs (/opt/rustwide/target/debug/deps/hedge-a68d46e45653d411)
[INFO] [stdout] 
[INFO] [stderr]      Running tests/limit/main.rs (/opt/rustwide/target/debug/deps/limit-e60fd95f91d00cae)
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr]      Running tests/load_shed/main.rs (/opt/rustwide/target/debug/deps/load_shed-8ab69d184c042c16)
[INFO] [stdout] 
[INFO] [stderr]      Running tests/ready_cache/main.rs (/opt/rustwide/target/debug/deps/ready_cache-97c96650406704b8)
[INFO] [stdout] 
[INFO] [stderr]      Running tests/retry/main.rs (/opt/rustwide/target/debug/deps/retry-c25b8646d3e14a7c)
[INFO] [stdout] running 0 tests
[INFO] [stderr]      Running tests/spawn_ready/main.rs (/opt/rustwide/target/debug/deps/spawn_ready-1ba7ab9135765a16)
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]      Running tests/steer/main.rs (/opt/rustwide/target/debug/deps/steer-294e36ea22e5dcc8)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]      Running tests/util/main.rs (/opt/rustwide/target/debug/deps/util-122a3f3f31990021)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests erkpht_tower
[INFO] [stdout] 
[INFO] [stdout] running 4 tests
[INFO] [stdout] test src/builder/mod.rs - builder::ServiceBuilder (line 90) ... FAILED
[INFO] [stdout] test src/builder/mod.rs - builder::ServiceBuilder (line 73) ... FAILED
[INFO] [stdout] test src/builder/mod.rs - builder::ServiceBuilder (line 31) ... FAILED
[INFO] [stdout] test src/builder/mod.rs - builder::ServiceBuilder (line 52) ... FAILED
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/builder/mod.rs - builder::ServiceBuilder (line 90) stdout ----
[INFO] [stdout] error[E0433]: cannot find module or crate `tower` in this scope
[INFO] [stdout]   --> src/builder/mod.rs:92:5
[INFO] [stdout]    |
[INFO] [stdout] 92 | use tower::builder::ServiceBuilder;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `tower`
[INFO] [stdout]   --> src/builder/mod.rs:91:5
[INFO] [stdout]    |
[INFO] [stdout] 91 | use tower::Service;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0432, E0433.
[INFO] [stdout] For more information about an error, try `rustc --explain E0432`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/builder/mod.rs - builder::ServiceBuilder (line 73) stdout ----
[INFO] [stdout] error[E0433]: cannot find module or crate `tower` in this scope
[INFO] [stdout]   --> src/builder/mod.rs:75:5
[INFO] [stdout]    |
[INFO] [stdout] 75 | use tower::builder::ServiceBuilder;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `tower`
[INFO] [stdout]   --> src/builder/mod.rs:74:5
[INFO] [stdout]    |
[INFO] [stdout] 74 | use tower::Service;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0432, E0433.
[INFO] [stdout] For more information about an error, try `rustc --explain E0432`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/builder/mod.rs - builder::ServiceBuilder (line 31) stdout ----
[INFO] [stdout] error[E0433]: cannot find module or crate `tower` in this scope
[INFO] [stdout]   --> src/builder/mod.rs:35:5
[INFO] [stdout]    |
[INFO] [stdout] 35 | use tower::builder::ServiceBuilder;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `tower`
[INFO] [stdout]   --> src/builder/mod.rs:34:5
[INFO] [stdout]    |
[INFO] [stdout] 34 | use tower::Service;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0432, E0433.
[INFO] [stdout] For more information about an error, try `rustc --explain E0432`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/builder/mod.rs - builder::ServiceBuilder (line 52) stdout ----
[INFO] [stdout] error[E0433]: cannot find module or crate `tower` in this scope
[INFO] [stdout]   --> src/builder/mod.rs:54:5
[INFO] [stdout]    |
[INFO] [stdout] 54 | use tower::builder::ServiceBuilder;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `tower`
[INFO] [stdout]   --> src/builder/mod.rs:53:5
[INFO] [stdout]    |
[INFO] [stdout] 53 | use tower::Service;
[INFO] [stdout]    |     ^^^^^ use of unresolved module or unlinked crate `tower`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `tower`, use `cargo add tower` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0432, E0433.
[INFO] [stdout] For more information about an error, try `rustc --explain E0432`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout]     src/builder/mod.rs - builder::ServiceBuilder (line 31)
[INFO] [stdout]     src/builder/mod.rs - builder::ServiceBuilder (line 52)
[INFO] [stdout]     src/builder/mod.rs - builder::ServiceBuilder (line 73)
[INFO] [stdout]     src/builder/mod.rs - builder::ServiceBuilder (line 90)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 0 passed; 4 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.19s
[INFO] [stdout] 
[INFO] [stderr] error: doctest failed, to rerun pass `--doc`
[INFO] running `Command { std: "docker" "inspect" "09c4601ba6cc94ca6961dbcafcc1fecfa86ddf5e06e59f82e243348229887719", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "09c4601ba6cc94ca6961dbcafcc1fecfa86ddf5e06e59f82e243348229887719", kill_on_drop: false }`
[INFO] [stdout] 09c4601ba6cc94ca6961dbcafcc1fecfa86ddf5e06e59f82e243348229887719
