NIMChatExtendBasicInfo 成员列表

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

	fromAccount	NIMChatExtendBasicInfo
-	initWithMessage:	NIMChatExtendBasicInfo
	messageID	NIMChatExtendBasicInfo
	serverID	NIMChatExtendBasicInfo
	session	NIMChatExtendBasicInfo
	timestamp	NIMChatExtendBasicInfo
	toAccount	NIMChatExtendBasicInfo
	type	NIMChatExtendBasicInfo