a value of type <a href="#type-transitive_callee_kind"><code>transitive_callee_kind</code></a> into a JSON string.</p><ul class="at-tags"><li class="parameter"><span class="at-tag">parameter</span> <span class="value">len</span> <p>specifies the initial length of the buffer used internally. Default: 1024.</p></li></ul></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-read_transitive_callee_kind"><a href="#val-read_transitive_callee_kind" class="anchor"></a><code><span><span class="