observe_export_resource_data/2
mod_export - fetch a row for the export, can return a list of rows, a binary, and optionally a continuation state. Where Values is [ term() ], i.e. a list of opaque values, to be formatted with #export_resource_format. Return the empty list of values to signify the end of the data stream.
Type:
Return:
{ok, Values|binary()}, {ok, Values|binary(), ContinuationState} or {error, Reason}
#export_resource_data{} properties:
- dispatch:
atom - id:
m_rsc:resource_id()|undefined - content_type:
binary - state:
term