code: public ContactHeader createContactHeader(String displayName, String userName, boolean usePublicAddress) {
  		return createContactHeader(displayName, userName, usePublicAddress, null);
  	}
docs: Create a Contact Header based on the host, port and transport of this listening point
  @param usePublicAddress if true, the host will be the global ip address found by STUN otherwise
  it will be the local network interface ipaddress
  @param displayName the display name to use
  @return the Contact header