combine 4.5.0

# rustc version
rustc 1.50.0-nightly (0edce6f4b 2020-12-24)
# docs.rs version
docsrs 0.6.0 (aef82af 2020-12-24)

# build log
[INFO] running `Command { std: "docker" "create" "-v" "/home/cratesfyi/workspace/builds/combine-4.5.0/target:/opt/rustwide/target:rw,Z" "-v" "/home/cratesfyi/workspace/builds/combine-4.5.0/source:/opt/rustwide/workdir:ro,Z" "-v" "/home/cratesfyi/workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/home/cratesfyi/workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "DOCS_RS=1" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "3221225472" "--cpus" "2" "--user" "1001:1001" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+nightly" "rustdoc" "--lib" "-Zrustdoc-map" "--all-features" "-Zunstable-options" "--config=doc.extern-map.registries.crates-io=\"https://docs.rs\"" "-j2" "--" "--cfg" "docsrs" "-Z" "unstable-options" "--resource-suffix" "-20201224-1.50.0-nightly-0edce6f4b" "--static-root-path" "/" "--cap-lints" "warn" "--disable-per-crate-search", kill_on_drop: false }`
[INFO] [stdout] fbf41a0747163a129fd515a0c9692a131af10fafe6480ec53cec14be1ce4e3dc
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "fbf41a0747163a129fd515a0c9692a131af10fafe6480ec53cec14be1ce4e3dc", kill_on_drop: false }`
[INFO] [stderr] /opt/crates-build-env/entrypoint.sh: line 7: /etc/hosts: Permission denied
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.48
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling proc-macro-hack v0.5.19
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling proc-macro-nested v0.1.6
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking futures-core v0.3.8
[INFO] [stderr]     Checking pin-project-lite v0.1.11
[INFO] [stderr]     Checking once_cell v1.5.2
[INFO] [stderr]     Checking futures-sink v0.3.8
[INFO] [stderr]     Checking bytes v0.5.6
[INFO] [stderr]     Checking futures-io v0.3.8
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]     Checking bytes v1.0.0
[INFO] [stderr]     Checking regex-syntax v0.6.21
[INFO] [stderr]     Checking pin-project-lite v0.2.0
[INFO] [stderr]    Compiling tokio v1.0.0
[INFO] [stderr]    Compiling tokio v0.3.3
[INFO] [stderr]     Checking thread_local v1.0.1
[INFO] [stderr]     Checking futures-task v0.3.8
[INFO] [stderr]     Checking futures-channel v0.3.8
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking aho-corasick v0.7.15
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking net2 v0.2.35
[INFO] [stderr]     Checking regex v1.4.2
[INFO] [stderr]     Checking mio v0.6.22
[INFO] [stderr]    Compiling pin-project-internal v1.0.1
[INFO] [stderr]    Compiling tokio-macros v1.0.0
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]    Compiling tokio-macros v0.3.1
[INFO] [stderr]    Compiling futures-macro v0.3.8
[INFO] [stderr]     Checking tokio v0.2.23
[INFO] [stderr]     Checking pin-project v1.0.1
[INFO] [stderr]     Checking futures-util v0.3.8
[INFO] [stderr]  Documenting combine v4.5.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 45.32s
[INFO] running `Command { std: "docker" "inspect" "fbf41a0747163a129fd515a0c9692a131af10fafe6480ec53cec14be1ce4e3dc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fbf41a0747163a129fd515a0c9692a131af10fafe6480ec53cec14be1ce4e3dc", kill_on_drop: false }`
[INFO] [stdout] fbf41a0747163a129fd515a0c9692a131af10fafe6480ec53cec14be1ce4e3dc