Race condition in TestAllocPutThenGet

[anthonyfok]

While investigating #54, I decided to see if adding the -race flag would help, and came across a different intermittent test failure.

--- FAIL: TestAllocPutThenGet (0.00s)
    alloc_test.go:72: cannot fetch written []bytes from pool
FAIL

Test command:

go clean -testcache
while go test -p=1 -race -vet=off github.com/xtaci/smux; do go clean -testcache; done

Thanks!

/cc @rogers0, @LocutusOfBorg

[xtaci]

I think it's a problem of the test function, instead of a race condition.

sync.Pool.Get() does not guarantee the data Put() into the pool will definitely be retrieved in the next Get().
check : https://golang.org/pkg/sync/#Pool.Get

Get selects an arbitrary item from the Pool, removes it from the Pool, and returns it to the caller. Get may choose to ignore the pool and treat it as empty. Callers should not assume any relation between values passed to Put and the values returned by Get.

[xtaci]

https://github.com/xtaci/smux/releases/tag/v1.3.5

[anthonyfok]

Thank you so much for your prompt resolution to this issue!
v1.3.5 works great here, and Ubuntu developers are in the process of pulling this new version into Eoan.