The ST_WithinFilter method provides an efficient test to determine if one geometry might be within the other. Returns 1 if
the geometry-expression might be within geo2, otherwise 0.
This test is less expensive than ST_Within, but may return 1 in some cases where the geometry-expression is not actually spatially within geo2.
Therefore, this method can be useful as a primary filter when further processing will determine if geometries interact in
the desired way.
The implementation of ST_WithinFilter relies upon metadata associated with the stored geometries. Because the available metadata
may change between server versions, depending upon how the data is loaded, or where ST_WithinFilter is used within a query,
the expression geometry-expression.ST_WithinFilter(geo2) can return different results when geometry-expression is not within geo2. Whenever geometry-expression is within geo2, ST_WithinFilter always returns 1.
This method can not be used with geometries in round-Earth spatial reference system.