Add support for sendmmsg/recvmmsg #1007

Job	Run time
Clippy	7s
Check (armv7-sony-vita-newlibeabihf)	31s
Check (aarch64-apple-ios)	8s
Check (i686-unknown-hurd-gnu)	32s
Docs (aarch64-apple-ios)	14s
Check (aarch64-linux-android)	11s
Docs (armv7-sony-vita-newlibeabihf)	26s
Docs (aarch64-linux-android)	12s
Check (x86_64-apple-darwin)	8s
Docs (i686-unknown-hurd-gnu)	28s
Rustfmt	6s
Docs (x86_64-apple-darwin)	16s
Check (x86_64-unknown-fuchsia)	11s
Docs (x86_64-unknown-fuchsia)	13s
Check (x86_64-pc-windows-msvc)	10s
Docs (x86_64-pc-windows-msvc)	14s
Test (stable)	17s
Check (x86_64-pc-solaris)	32s
Docs (x86_64-pc-solaris)	13s
Test (1.63.0)	3m 2s
Check (x86_64-unknown-freebsd)	22s
Docs (x86_64-unknown-freebsd)	16s
Check (x86_64-unknown-illumos)	21s
Test (beta)	23s
Docs (x86_64-unknown-illumos)	13s
Check (x86_64-unknown-linux-gnu)	12s
Test (nightly)	21s
Docs (x86_64-unknown-linux-gnu)	12s
Check (x86_64-unknown-linux-musl)	9s
Test (macos)	12s
Docs (x86_64-unknown-linux-musl)	14s
Check (x86_64-unknown-netbsd)	15s
Test (windows)	46s
Check (x86_64-unknown-redox)	14s
Docs (x86_64-unknown-netbsd)	14s
Check (armv7-linux-androideabi)	13s
Docs (x86_64-unknown-redox)	14s
Check (i686-linux-android)	12s
Docs (armv7-linux-androideabi)	13s
Docs (i686-linux-android)	14s
	13m 41s

Provide feedback