Prevent socket leaks due to post-open exceptions

[armanbilge]

Currently when opening an socket, other exception-throwing operations were attempted within the same delay block. If these operations threw an exception, the socket acquire would be deemed failed, and the resource finalizer which closes the socket would not run, thereby leaking the socket.

The acquire phase of the resource must end as soon as the socket is opened; this ensures that it will be closed even if there are subsequent errors.

H/t the native cross-build for discovering this one 😁

[armanbilge]

Forgot to mention: I couldn't think of how to write a regression test for this one. Since it requires an error to occur when connecting the client / starting the server, we don't get a handle to the Socket in these cases and thus cannot verify if it is indeed closed.

[armanbilge]

We exercise a BindException in our test suite, which was causing the open socket to leak.

fs2/io/shared/src/test/scala/fs2/io/net/tcp/SocketSuite.scala

Lines 171 to 177 in 0e573f2

	bindAddress <- Network[IO].serverResource(Some(ip"127.0.0.1")).map(_._1)
	_ <- Network[IO]
	.serverResource(Some(bindAddress.host), Some(bindAddress.port))
	.void
	.recover { case ex: BindException =>
	assertEquals(ex.getMessage, "Address already in use")
	}