Snaps vertices to S2Cell centers at the given level. As a side effect,
this method also resets "snap_radius" to the minimum value allowed at
this level:
set_snap_radius(MinSnapRadiusForLevel(level))
This means that if you want to use a larger snap radius than the minimum,
you must call set_snap_radius() *after* calling set_level().
Snaps vertices to S2Cell centers at the given level. As a side effect, this method also resets "snap_radius" to the minimum value allowed at this level:
set_snap_radius(MinSnapRadiusForLevel(level))
This means that if you want to use a larger snap radius than the minimum, you must call set_snap_radius() *after* calling set_level().