="multi-line-signature">
      <span class="returntype"><a href="dart-async/ZoneUnaryCallback.html">ZoneUnaryCallback</a><span class="signature">&lt;<wbr><span class="type-parameter">R</span>, <span class="type-parameter">T</span>&gt;</span></span>
            <span class="name ">registerUnaryCallback</span>
&lt;<wbr><span class="type-parameter">R</span>, <span class="type-parameter">T</span>&gt;(<wbr><span class="parameter" id="registerUnaryCallback-param-callback"><span class="type-annotation">R</span> <s