wasi: sockets, use WSAPoll and GetOverlappedResult on Windows

[gaukas]

Current readSocket function for WASI sockets is implemented incorrectly on Windows and WASI polling an async socket for a long time will eventually get ERROR_WORKING_SET_QUOTA (1453):

Insufficient quota to complete the requested service.

A call to GetOverlappedResult is expected after each ERROR_IO_PENDING returned by ReadFile and that is what's missing in the current implementation. Besides that, ReadFile would create a background worker to keep on trying reading from the handle into the buf, which could result in data loss if we don't keep tracking of it. So we add a call to WSAPoll before calling ReadFile to observe how many bytes are ready to be read.

In this pull request, we modify how readSocket in internal/sysfs/file_windows.go is implemented by adding the following changes:

• Call WSAPoll before calling ReadFile, abort if no bytes are available no fd is ready to be read.
• Call GetOverlappedResult if ReadFile returns ERROR_IO_PENDING.
• Limit the read buffer's size according to how many bytes are ready to be read (see review comments)
• Cancel the ongoing overlapped read if it cannot be completed immediately.

[evacchi]

I would add a test case.

You can modify

wazero/internal/sysfs/sock_test.go

Line 50 in 009ee70

func TestTcpConnFile_Read(t *testing.T) {

to ensure that it also checks the conditions that caused this PR in the first place (You might need to modify the WASI test case)

You can also add a unit test to readSocket (add a test to file_test.go, there is none currently.)

You can do either or both. Thanks!

[evacchi]

clean up the commented out bits, if the tests pass then it should be good to go!