Java class to represent the DiameterIdentity AVP type.
The DiameterIdentity format is derived from the OctetString AVP Base Format.
DiameterIdentity = FQDN
DiameterIdentity value is used to uniquely identify a Diameter
node for purposes of duplicate connection and routing loop
The contents of the string MUST be the FQDN of the Diameter node.
If multiple Diameter nodes run on the same host, each Diameter
node MUST be assigned a unique DiameterIdentity. If a Diameter
node can be identified by several FQDNs, a single FQDN should be
picked at startup, and used as the only DiameterIdentity for that
node, whatever the connection it is sent on.