Warning: variable does not need to be mutable

[iwconfig]

Occurs when compiling

warning: doc comment not used by rustdoc
  --> src/apresolve.rs:10:1
   |
10 | error_chain! { }
   | ^^^^^^^^^^^^^^^^
   |
   = note: #[warn(unused_doc_comment)] on by default
   = note: this error originates in a macro outside of the current crate

warning: doc comment not used by rustdoc
  --> src/apresolve.rs:10:1
   |
10 | error_chain! { }
   | ^^^^^^^^^^^^^^^^
   |
   = note: this error originates in a macro outside of the current crate

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:167:29
    |
167 |                         let mut msg = msg.mut_build_info();
    |                             ^^^^^^^
    |
    = note: #[warn(unused_mut)] on by default

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:178:29
    |
178 |                         let mut msg =
    |                             ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:201:29
    |
201 |                         let mut msg =
    |                             ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:318:25
    |
318 |                     let mut msg = msg.mut_login_credentials();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:325:25
    |
325 |                     let mut msg = msg.mut_system_info();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:448:25
    |
448 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:454:25
    |
454 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:460:25
    |
460 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:466:25
    |
466 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:472:25
    |
472 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:478:25
    |
478 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:484:25
    |
484 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^

warning: variable does not need to be mutable
   --> /tmp/spotify-connect-scrobbler/target/debug/build/spotify-connect-scrobbler-93e09b0021019303/out/lib.rs:500:25
    |
500 |                     let mut msg = repeated.push_default();
    |                         ^^^^^^^