def _should_save_report_msg(msg):
    """Returns True if the given ForwardMsg should be serialized into
    a shared report.

    We serialize report & session metadata and deltas, but not transient
    events such as upload progress.

    """
    msg_type = msg.WhichOneof('type')
    return (msg_type == 'initialize' or msg_type == 'new_report' or 
        msg_type == 'delta')
