Member</span> pair of the innermost JSON <span class='json'>Object</span>
opened with <span class='api-name'>with-object</span> in the dynamic context.  <span class='arg-name'>Key</span> and <span class='arg-name'>value</span> are
encoded using the <span class='api-name'>encode-json</span> generic function, so they both must be
of a type for which an <span class='api-name'>encode-json</span> method is defined.  If <span class='arg-name'>key</span> does not
encode to a <span class='json'>String</span>, its J