成员的完整列表，这些成员属于 com.hyphenate.chat.EMConferenceAttribute.Action,包括所有继承而来的类成员

ADD (定义于 com.hyphenate.chat.EMConferenceAttribute.Action)	com.hyphenate.chat.EMConferenceAttribute.Action
DELETE (定义于 com.hyphenate.chat.EMConferenceAttribute.Action)	com.hyphenate.chat.EMConferenceAttribute.Action
UPDATE (定义于 com.hyphenate.chat.EMConferenceAttribute.Action)	com.hyphenate.chat.EMConferenceAttribute.Action