Stream file attachment

For an attachment of type FILE or IMAGE, clients must first stream files to the server and include a GUID in the attachmentInput parameter, and then call one of the attach tasks.

The attach tasks include attachTopic, attachNewTopic, attachAction, and attachNewAction.

The task uses a query parameter to specify the resulting guid. The guid parameter is required. The body of the message must be a BINARY_INPUT_STREAM containing the file contents.