Simplified timers and a bugfix

[Ralith]

Fixes #574.

[github-actions]

Pull Request Test Coverage Report for Build 0c920c16f7bc5ff86018fe8b72273a4b53095a17-PR-582

• 60 of 67 (89.55%) changed or added relevant lines in 3 files are covered.
• 35 unchanged lines in 27 files lost coverage.
• Overall coverage increased (+0.06%) to 70.656%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
quinn-proto/src/connection.rs	47	54	87.04%

Files with Coverage Reduction	New Missed Lines	%
quinn-proto/src/shared.rs	1	49.22%
quinn-proto/src/spaces.rs	1	87.43%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/bytes-0.5.3/src/buf/buf_mut.rs	1	58.82%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/bytes-0.5.3/src/bytes_mut.rs	1	28.87%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-channel-0.3.1/src/mpsc/mod.rs	1	82.17%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-channel-0.3.1/src/mpsc/queue.rs	1	89.36%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-channel-0.3.1/src/oneshot.rs	1	80.22%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.1/src/future/maybe_done.rs	1	72.73%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/http-0.2.0/src/byte_str.rs	1	0.0%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/http-0.2.0/src/header/map.rs	1	50.75%

Totals
Change from base Build 715ab1678d451d5b6cae2e89f8fc233776b971d7:	0.06%
Covered Lines:	9978
Relevant Lines:	14122

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💛 - Coveralls

[djc]

Just a bunch of style nits. Looks good to me, nice simplification!

[Ralith]

Resolved comments, resulting in another 80 lines or so saved!