Gets or sets the domain value used for Jabber IDs.
A Jabber ID (JID) is a unique identifier of the format "User@Domain/Resource". user@domain denotes the account by username and domain. The Resource is given during the login process to distinguish individual connections under the same account. If the IMServer contains multiple domains, this property setting allows the user to specify the domain under which to login.
If Domain is empty, the value in IMServer is used by default when creating the client's JID.