This class represents the string form of the address of
a communications end-point.
It consists of a type that describes the communication mechanism
and a string contents specific to that communication mechanism.
The format and interpretation of
the address type and the contents of the address are based on
the agreement of three parties: the client that uses the address,
the object/server that can be reached using the address, and the
administrator or program that creates the address.
An example of a string reference address is a host name.
Another example of a string reference address is a URL.
A string reference address is immutable:
once created, it cannot be changed. Multithreaded access to
a single StringRefAddr need not be synchronized.