feat: Add UDP GRO option

[XAMPPRocky]

Allows setting UDP_GRO on the socket.

https://www.man7.org/linux/man-pages/man7/udp.7.html

Enables UDP receive offload. If enabled, the socket may
receive multiple datagrams worth of data as a single large
buffer, together with a cmsg(3) that holds the segment
size. This option is the inverse of segmentation offload.
It reduces receive cost by handling multiple datagrams
worth of data as a single large packet in the kernel
receive path, even when that exceeds MTU. This option
should not be used in code intended to be portable.

[Thomasdezeeuw]

Since this Linux only, can you put in the sys/unix.rs file:

socket2/src/sys/unix.rs

Line 763 in 3a93893

impl SockAddr {

Could also you make sure it's order by option name.

Can you add the appropriate attributes, e.g. see

socket2/src/sys/unix.rs

Lines 791 to 795 in 3a93893

	#[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
	#[cfg_attr(
	docsrs,
	doc(cfg(all(feature = "all", any(target_os = "android", target_os = "linux"))))
	)]

Finally can you add a test? A simple set and get test is sufficient, see

socket2/tests/socket.rs

Line 1357 in 3a93893

test!(reuse_port, set_reuse_port(true));

[XAMPPRocky]

@Thomasdezeeuw Thank you, I've implemented your feedback, the only thing I wasn't 100% sure on was "Could also you make sure it's order by option name." let me know if I need to make more changes

[Thomasdezeeuw]

Thanks @XAMPPRocky