abstract fun addPersistentStyleCustomLayer(@NonNull layerId: String, @NonNull layerHost: CustomLayerHost, @Nullable layerPosition: LayerPosition): Expected<String, None>

Adds a new [style custom layer]( Whenever a new style is being parsed and currently used style has persistent layers, an engine will try to do following: - keep the persistent layer at its relative position - keep the source used by a persistent layer - keep images added through `addStyleImage` method In cases when a new style has the same layer, source or image resource, style's resources would be used instead and `MapLoadingError` event will be emitted.


A string describing an error if the operation was not successful, or empty otherwise.



A style layer identifier.


The `custom layer host`.


If not empty, the new layer will be positioned according to `layer position` parameters.