-Groups have the following (case-sensitive) properties:
-* Id<ay> (read-only) : Byte array representing the internal group identifier
-* Name<s> : Display name of the group
-* Description<s> : Description of the group
-* Avatar<s> (write-only) : Filename of the avatar
-* IsBlocked<b> : true=member will not receive group messages; false=not blocked
-* IsMember<b> (read-only) : always true (object path exists only for group members)
-* IsAdmin<b> (read-only) : true=member has admin privileges; false=not admin
-* MessageExpirationTimer<i> : int32 representing message expiration time for group
-* Members<as> (read-only) : String array of group members' phone numbers
-* PendingMembers<as> (read-only) : String array of pending members' phone numbers
-* RequestingMembers<as> (read-only) : String array of requesting members' phone numbers
-* Admins<as> (read-only) : String array of admins' phone numbers
-* PermissionAddMember<s> : String representing who has permission to add members
-** ONLY_ADMINS, EVERY_MEMBER
-* PermissionEditDetails<s> : String representing who may edit group details
-** ONLY_ADMINS, EVERY_MEMBER
-* PermissionSendMessage<s> : String representing who post messages to group
-** ONLY_ADMINS, EVERY_MEMBER (note that ONLY_ADMINS is equivalent to IsAnnouncementGroup)
-* GroupInviteLink<s> (read-only) : String of the invitation link (starts with https://signal.group/#)