public XAConnection xaConnection(XAConnection xaConnection) {
    return TracingXAConnection.create(xaConnection, this);
  }
@Test void xaConnection_doesntDoubleWrap() {
    XAConnection wrapped = jmsTracing.xaConnection(mock(XAConnection.class));
    assertThat(jmsTracing.xaConnection(wrapped))
      .isSameAs(wrapped);
  }