Specifies the value to filter for. Value should be an object which specifies attribute/value pairs to filter on. The op will be applied to each attribute/value pair and
the whole will be AND'd. For subobjects, please specify them in a nested structure.
Specifies a filter function which has the same signature as the the callback
which is specified for the JS Array.filter():
This function will be optionally used by the DataProvider to do local filtering.
This function is required by the DataProvider so that it is possible for DataProvider
implementations to at least do local filtering.