diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 68b5f30..501202b 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -669,6 +669,7 @@
 void mbedtls_ssl_send_flight_completed( mbedtls_ssl_context *ssl );
 void mbedtls_ssl_recv_flight_completed( mbedtls_ssl_context *ssl );
 int mbedtls_ssl_resend( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl );
 #endif
 
 /* Visible for testing purposes only */