[PUB-1828] Add Objects spec for object and map entry tombstones, and OBJECT_DELETE message handling

textile/features.textile

@@ -1515,6 +1515,7 @@ h4. ObjectMessage
 ** @(OM2f)@ @operation@ @ObjectOperation@ object. Mutually exclusive with the @object@ field. This field is only set on object messages if the @action@ field of the @ProtocolMessage@ encapsulating it is @OBJECT@
 ** @(OM2g)@ @object@ @ObjectState@ object. Mutually exclusive with the @operation@ field. This field is only set on object messages if the @action@ field of the @ProtocolMessage@ encapsulating it is @OBJECT_SYNC@
 ** @(OM2h)@ @serial@ string - an opaque string that uniquely identifies this object message
+** @(OM2j)@ @serialTimestamp@ Time - a timestamp from the @serial@ field
 ** @(OM2i)@ @siteCode@ string - an opaque string used as a key to update the map of @serial@ values on an object
 * @(OM3)@ The size of the @ObjectMessage@ for "TO3l8":#TO3l8 is calculated as follows:
 ** @(OM3a)@ The size is the sum of the sizes of the @clientId@, @operation@, @object@, and @extras@ properties
@@ -1621,6 +1622,7 @@ h4. ObjectsMapEntry
 * @(OME2)@ The attributes available in an @ObjectsMapEntry@ are:
 ** @(OME2a)@ @tombstone@ boolean - indicates whether the map entry has been removed
 ** @(OME2b)@ @timeserial@ string - the @serial@#OM2h value of the last operation that was applied to the map entry
+** @(OME2d)@ @serialTimestamp@ Time - a timestamp from the @timeserial@ field. It is only present if @tombstone@ is @true@
 ** @(OME2c)@ @data@ @ObjectData@ object - the data that represents the value of the map entry.
 * @(OME3)@ The size of the @ObjectsMapEntry@ is calculated as follows:
 ** @(OME3a)@ It is equal to the size of the @data@ property
@@ -1857,7 +1859,7 @@ h4. ConnectionDetails
 ** @(CD2f)@ @connectionStateTtl@ is the duration that Ably will persist the connection state when a Realtime client is abruptly disconnected
 ** @(CD2g)@ @serverId@ string is a unique identifier for the front-end server that the client has connected to. This server ID is only used for the purposes of debugging
 ** @(CD2h)@ @maxIdleInterval@ is the maximum length of time in milliseconds that the server will allow no activity to occur in the server->client direction. After such a period of inactivity, the server will send a @HEARTBEAT@ or transport-level ping to the client. If the value is 0, the server will allow arbitrarily-long levels of inactivity.
-
+** @(CD2i)@ @objectsGCGracePeriod@ integer - the length of time, in milliseconds, that the client library must wait before releasing resources for tombstoned objects and map entries (see "RTO10":../objects-features#RTO10)
 h4. ChannelProperties
 * @(CP1)@ properties of a channel and its state
 * @(CP2)@ The attributes of @ChannelProperties@ consist of:
@@ -2570,6 +2572,7 @@ class ConnectionDetails: // CD*, internal
   maxMessageSize: Int // CD2c
   serverId: String // CD2g
   maxIdleInterval: Duration // CD2h
+  objectsGCGracePeriod: Int // CD2i
 
 class Message: // TM*
   constructor(name: String?, data: Data?) // TM4
@@ -2619,6 +2622,7 @@ class ObjectMessage // OM*, internal
   operation: ObjectOperation? // OM2f
   object: ObjectState? // OM2g
   serial: String // OM2h
+  serialTimestamp: Time? // OM2j
   siteCode: String // OM2i
 
 class ObjectOperation // OOP*, internal
@@ -2657,6 +2661,7 @@ class ObjectsCounter // OCN*, internal
 class ObjectsMapEntry // OME*, internal
   tombstone: Boolean? // OME2a
   timeserial: String? // OME2b
+  serialTimestamp: Time? // OME2d
   data: ObjectData? // OME2c
 
 class ObjectData // OD*, internal