Pull In Downstream Fixes

[pnegahdar]

I was looking through the fork graph and found a few commits that might be of interest that should perhaps be merged in.

• Sniff Timeouts: https://github.com/kathentgist/cmux/commit/2c4d82ed387abf35c7ba4cf0d8c9dda287bd7067
• Mid-match cancelations: https://github.com/zhangqibupt/cmux/commit/cdd3c6382f7f597815fa29ef73de599391deca22
• Close and cleanup: https://github.com/michaelyou/cmux/commit/079c26e7d242e6c2822c6b0801defd768a9e5e17

[oldgalileo]

Specifically

• Close and cleanup: michaelyou@079c26e

is a good candidate for merging. Good content, nothing flagrantly wrong. Didn't read through the others because I'm lazy so I can't speak to them.