API Function for Publishing Messages

Purpose: Returns an output message from the plugin. This function can be called multiple times to return multiple messages.

C8Status C8RpcReturnMessage(C8Rpc *rpcctx, C8Message *msgptr); – If the plugin does not want to return any messages then this function should not be called. Note that the output message schema must match the schema returned by the C8RpcGetOutputSchema() function.
Parameters:
- rpcctx: A pointer to the "context" (data structure) for this particular instance of the plugin.
- msgptr: A pointer to an empty message that the server can "fill in".
Returns: C8_OK on success, C8_FAIL if anything goes wrong.