Emit the query-data signal. This function is called
to query for data just before rendering a cell. This is called from the
gsv.SourceGutter Implementations can override the default signal handler or
can connect a signal handler externally to the
query-data signal.
Emit the query-data signal. This function is called to query for data just before rendering a cell. This is called from the gsv.SourceGutter Implementations can override the default signal handler or can connect a signal handler externally to the query-data signal.