The syntax of this message is specified in section

The RunspacePool MUST be in an Opened state (section when this message is sent.

This message MUST be sent to the server's RunspacePool. Before sending this message, the client MUST construct a unique integer identifier to represent the message and store it in the RunspacePool's CI table (section In response to this message, the server will send a RUNSPACE_AVAILABILITY message (section which the client will use to update the RunspacePool CI table (section by removing the appropriate integer identifier.