<MessageHeader xmlns="http://hl7.org/fhir">
   <id value="1156783"/>
   <meta>
      <versionId value="1"/>
      <lastUpdated value="2019-01-12T14:42:46.423+00:00"/>
   </meta>
   <event>
      <system value="http://hl7.org/fhir/message-events"/>
      <code value="communication-request"/>
   </event>
   <receiver>
      <reference value="http://example.org/fhir/Practitioner/bser-referral-recipient-example"/>
   </receiver>
   <sender>
      <reference value="http://example.org/fhir/Practitioner/bser-referral-initiator-example"/>
   </sender>
   <timestamp value="2018-01-10T09:10:14Z"/>
   <source>
      <name value="Example Corp. Endpoint"/>
      <endpoint value="http://example.org/fhir"/>
   </source>
   <reason>
      <coding>
         <system value="http://hl7.org/fhir/ValueSet/message-reason-encounter"/>
      </coding>
   </reason>
   <focus>
      <reference value="http://example.org/fhir/ReferralRequest/bser-referral-request-example"/>
   </focus>
</MessageHeader>