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

account_id_	NIMSignalingInviteParam
channel_id_	NIMSignalingInviteParam
custom_info_	NIMSignalingInviteParam
offline_enabled_	NIMSignalingInviteParam
push_info_	NIMSignalingInviteParam
request_id_	NIMSignalingInviteParam