Fix for TLS v1.3 in non-blocking loosing return code from SendBuffered. Example: SendBuffered returns WANT_WRITE (-327) and sets ssl->error, then below it was doing ssl->error = ret where ret = 0.

Author: dgarske

src/tls13.c

@@ -11954,7 +11954,7 @@ int wolfSSL_connect_TLSv13(WOLFSSL* ssl)
         && ssl->error != WC_PENDING_E
     #endif
     ) {
-        if ((ssl->error = SendBuffered(ssl)) == 0) {
+        if ((ret = SendBuffered(ssl)) == 0) {
             if (ssl->fragOffset == 0 && !ssl->options.buildingMsg) {
                 if (advanceState) {
 #ifdef WOLFSSL_DTLS13