OptionalfeatureThe feature's ID. Setting or reading state needs it. Without it,
MapHandle.removeFeatureState() removes the state of every feature in the
source layer.
OptionalsourceThe source layer, for a vector source. Empty for other sources.
OptionalstateThe one key that MapHandle.removeFeatureState() removes. It needs
feature_id. Empty removes every key.
The features whose state to set, read, or remove.
See
mln_feature_state_selectorin the C API reference.