t entirely fit in memory.
          </li>
<li class="listitem">
            A body produced incrementally from coroutine output.
          </li>
<li class="listitem">
            A body represented by zero or more buffers already in memory.
          </li>
<li class="listitem">
            A body whose size is not known ahead of time.
          </li>
<li class="listitem">
            Body data generated dynamically from other threads.
          </li>
<li class="listitem">
            Body data computed algo