recordSpan = (stream) => {
    serverConnections++

    // drain reads to make sure everything finishes properly
    stream.on('data', () => {})

    // detach as soon as we connect
    // end the stream -- sends back a STATUS OK
    stream.end()
  }
Implements the recordSpan RPC method, used below.

While the test functions correctly with a valid connection,
we ensure proper connection / OK status handling for this case.
@param stream