public final Handle getSharedHandle() {
        if (sharedHandle == null) {
            throw new IllegalStateException("sharedHandle is null!");
        }

        return sharedHandle;
    }
Returns a shared {@link Handle} used by the extension. This handle exists during the lifetime of the extension and is connected to the data source used
by the extension. Multiple calls to this method always return the same instance.

@return A {@link Handle} instance.
testing/src/main/java/org/jdbi/v3/testing/junit5/JdbiExtension.java