Enable leak detection

core/pom.xml

@@ -70,7 +70,7 @@
         <dependency>
             <groupId>com.zaxxer</groupId>
             <artifactId>HikariCP</artifactId>
-            <version>4.0.3</version>
+            <version>5.0.2-SNAPSHOT</version>
             <exclusions>
                 <!-- HikariCP uses an old version of this API that has a typo in the service interface -->
                 <!-- We will use the api provided by the jdk14 dependency -->

core/src/main/java/com/github/games647/fastlogin/core/storage/MySQLStorage.java

@@ -55,6 +55,9 @@ public class MySQLStorage extends SQLStorage {
         config.addDataSourceProperty("useSSL", useSSL);
         config.addDataSourceProperty("requireSSL", useSSL);
 
+        //enable leak detection of holding connections
+        config.setLeakDetectionThreshold(2000);
+
         // adding paranoid, hides hostname, username, version and so
         // could be useful for hiding server details
         config.addDataSourceProperty("paranoid", true);