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

member_list	NIMQChatServerGetMembersResp
member_list_count	NIMQChatServerGetMembersResp
res_code	NIMQChatServerGetMembersResp
user_data	NIMQChatServerGetMembersResp