option</span> <span class="xref-unresolved">Eio</span>.Promise.t</span> <span class="arrow">&#45;&gt;</span></span> <span class="type-var">'a</span>)</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="type-var">'a</span> <a href="#type-handler">handler</a></span></span></code></div><div class="spec-doc"><p><code>client_streaming ~f write read</code> sets up the sending and receiving logic using <code>write</code> and <code>read</code>, then calls <code>f</code> with a push function for 