Support Unix domain sockets communication on Linux, MacOS and Android.
Changes:
1. Add a field for InternetAddressType named unix.
2. Constructor of InternetAddress gains one more optional field: type. InternetAddress(String address, {InternetAddressType type});
3. Add another constructor to InternetAddress which taks raw address/path for ip/unix addresses as an argument. InternetAddress.fromRawAddress(Uint8List rawAddress, {InternetAddressType type});
The operation for unix domain sockets communication is basically the same as normal sockets except an InternetAddress with type unix should be passed.
Change-Id: I6a1135bbdd7f4e4fc745ccf8f95dec5272b6839b
Bug: https://github.com/dart-lang/sdk/issues/21403
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/125932
Commit-Queue: Zichang Guo <zichangguo@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Zichang Guo