<div class="content" name="Message_Packet_Structure" uuid="f9e71595-339a-4cc4-8341-371e0a4cb232"><p>The <b>Message Packet Structure</b> is the data structure
that contains the <b>UserMessage</b> and other headers that represent the
payload that is transferred across the wire as a result of a remote read
operation. More details are specified in R_StartReceive (Opnum
7) (section <span><a href="1bd20827-f774-4279-ae8d-4898d6faf6e9" data-linktype="relative-path">3.1.4.7)</a></span> and
R_StartTransactionalReceive (Opnum 13) (section <span><a href="c5296e0c-9e12-4fe8-a25d-56924982ac3e" data-linktype="relative-path">3.1.4.13)</a></span>.</p><table>
 <tbody><tr>
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  <th><p>1<br/>0</p></th>
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 </tr>
 <tr>
  <td colspan="32">UserMessage (variable)</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">ExtensionHeader</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">SubqueueHeader (148 bytes)</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">DeadLetterHeader (variable)</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">ExtendedAddressHeader (28 bytes)</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
</tbody></table><p><b>UserMessage (variable): </b>A <span><a href="90345101-8295-4912-b1b2-bbe88531af93" data-linktype="relative-path">UserMessage
(section 2.2.5.1)</a></span> structure.</p><p><b>ExtensionHeader (12 bytes): </b>An <span><a href="baf230bf-7f15-4d03-bd1d-f8276608a955" data-linktype="relative-path">ExtensionHeader
(section 2.2.5.2)</a></span> structure.</p><p><b>SubqueueHeader (148 bytes): </b>A <span><a href="ee62651b-ade2-417c-91af-7a6cf6f3e86a" data-linktype="relative-path">SubqueueHeader
(section 2.2.5.3)</a></span> structure.</p><p><b>DeadLetterHeader (variable): </b> A <span><a href="377dc454-43ef-4c48-8c07-692de2fd9ec4" data-linktype="relative-path">DeadLetterHeader
(section 2.2.5.4)</a></span> structure. </p><p><b>ExtendedAddressHeader (28 bytes): </b>An <span><a href="20119e19-df2d-4c37-a739-eebad84cc83a" data-linktype="relative-path">ExtendedAddressHeader
(section 2.2.5.5)</a></span> structure.</p></div>