Allow accept() to return transient errors.

The original provision was added to align with preview3 streams that may only fail once. However, after discussing with Dan Gohman, we came to the conclusion that a stream of result<> could do the trick fine too.

Fixes: WebAssembly/wasi-sockets#22

crates/wasi/src/preview2/host/network.rs

@@ -90,7 +90,7 @@ impl<T: SystemError> From<T> for network::Error {
             Errno::TIMEDOUT => ErrorCode::Timeout,
             Errno::CONNREFUSED => ErrorCode::ConnectionRefused,
             Errno::CONNRESET => ErrorCode::ConnectionReset,
-            // Errno::CONNABORTED => ErrorCode::Todo, // FIXME
+            Errno::CONNABORTED => ErrorCode::ConnectionAborted,
             // Errno::INVAL => ErrorCode::Todo, // FIXME
             Errno::HOSTUNREACH => ErrorCode::RemoteUnreachable,
             Errno::HOSTDOWN => ErrorCode::RemoteUnreachable,

crates/wasi/wit/deps/sockets/network.wit

@@ -130,6 +130,9 @@ interface network {
 
 		/// The connection was reset.
 		connection-reset,
+
+		/// A connection was aborted.
+		connection-aborted,
 
 
 		// ### UDP SOCKET ERRORS ###

crates/wasi/wit/deps/sockets/tcp.wit

@@ -136,8 +136,8 @@ interface tcp {
 	/// # Typical errors
 	/// - `not-listening`: Socket is not in the Listener state. (EINVAL)
 	/// - `would-block`:   No pending connections at the moment. (EWOULDBLOCK, EAGAIN)
-	/// 
-	/// Host implementations must skip over transient errors returned by the native accept syscall.
+	/// - `connection-aborted`: An incoming connection was pending, but was terminated by the client before this listener could accept it. (ECONNABORTED)
+	/// - `new-socket-limit`:   The new socket resource could not be created because of a system limit. (EMFILE, ENFILE)
 	/// 
 	/// # References
 	/// - <https://pubs.opengroup.org/onlinepubs/9699919799/functions/accept.html>