diff --git a/src/MysqlClient.php b/src/MysqlClient.php
index a7d8aa8..2879ac2 100644
--- a/src/MysqlClient.php
+++ b/src/MysqlClient.php
@@ -8,6 +8,7 @@
 use React\Mysql\Io\Factory;
 use React\Promise\Deferred;
 use React\Promise\Promise;
+use React\Promise\PromiseInterface;
 use React\Socket\ConnectorInterface;
 use React\Stream\ReadableStreamInterface;