Implementation of SILC Socket Stream.  SILC Socket Stream can be used
 read data from and write data to a socket connection.  The SILC Socket
 Stream provides also Quality of Service (QoS) support that can be used
 to control the throughput of the stream.  It also supports both TCP and
 UDP, and IPv4 and IPv6.

 SILC Socket Stream is not thread-safe.  If the same socket stream must be
 used in multithreaded environment concurrency control must be employed.