Sets or clears the accumulate flag on this.
(The default value is true.) If set to false, this's data field will not be filled in after the body is fully sent/received, and the chunks that make up this may be discarded when they are no longer needed.
If you set the flag to false on the [class@Message] request_body of a client-side message, it will block the accumulation of chunks into this's data field, but it will not normally cause the chunks to be discarded after being written like in the server-side [class@Message] response_body case, because the request body needs to be kept around in case the request needs to be sent a second time due to redirection or authentication.
| this | |
| accumulate |
whether or not to accumulate body chunks in this |