def start_record():
    """
    Install an httplib wrapper that records but does not modify calls.
    """
    global record, playback, current
    if record:
        raise StateError("Already recording.")
    if playback:
        raise StateError("Currently playing back.")
    record = True
    current = ReplayData()
    install(RecordingHTTPConnection, RecordingHTTPSConnection)
Install an httplib wrapper that records but does not modify calls.