Prevent SIGPIPE on Darwin when writing to a closed core:net socket

[Feoramund]

Mimics behavior found on Linux implementation.

[laytan]

Should probably handle the EPIPE error too, it will now be a "bad enum value" error.

Linux does this:

		if errno == .EPIPE {
			// If the peer is disconnected when we are trying to send we will get an `EPIPE` error,
			// so we turn that into a clearer error
			return total_written, TCP_Send_Error.Connection_Closed