成员的完整列表，这些成员属于 NIMSignalingRejectParam,包括所有继承而来的类成员

account_id_	NIMSignalingRejectParam
channel_id_	NIMSignalingRejectParam
custom_info_	NIMSignalingRejectParam
offline_enabled_	NIMSignalingRejectParam
request_id_	NIMSignalingRejectParam