er, to which data will be read
                  and written during operations. For synchronous operations, the
                  type must support the SyncStream concept. For asynchronous operations,
                  the type must support the AsyncStream concept. This type will usually
                  be some variation of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identif