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:

first

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