flush TLS buffer

src/tls_mbed.c

@@ -204,11 +204,18 @@ long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
     tls->throttled_buf = (unsigned char *)buf; // MbedTLS code actually ignores
     tls->throttled_len = len; //  these, but let's play API rules
     return (long) len;  // already encripted that when throttled
-  }
+  } // if last chunk fails to be sent, it needs to be flushed
   if (n <= 0) return MG_IO_ERR;
   return n;
 }
 
+void mg_tls_flush(struct mg_connection *c) {
+  if (c->is_tls_throttled) {
+    long n = mbedtls_ssl_write(&tls->ssl, tls->throttled_buf, tls->throttled_len);
+    c->is_tls_throttled = (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE);
+  }
+}
+
 void mg_tls_ctx_init(struct mg_mgr *mgr) {
   struct mg_tls_ctx *ctx = (struct mg_tls_ctx *) calloc(1, sizeof(*ctx));
   if (ctx == NULL) {