public void clearLastConnection() {
        this.lastConnection = null;
    }
Returns the last connection handed out by this extension. This is <b>not</b> a general
purpose API but is intended for tests that need to compare connection objects between a
handle and what the extension has handed out.
<br>
This API is <b>not multi-thread safe</b> and will not work if the extension is shared between
multiple threads.
@return A connection object. Can be null if no connection had been handed out.
core/src/test/java/org/jdbi/v3/core/junit5/H2DatabaseExtension.java