p:set-properties-021 (AB)

The pipeline

<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
   <p:output port="result"/>
   <p:set-properties properties="map{'content-type':'application/octet-stream'}" merge="true">
      <p:with-input>
         <p:inline>
            <doc/>
         </p:inline>
      </p:with-input>
   </p:set-properties>
</p:declare-step>