setVanishingOffset
Sets the value of the vanishing point of the route line to the value specified. This is used for the vanishing route line feature and is only applicable only if the feature was enabled in the MapboxRouteLineApiOptions.
Return
a state representing the side effects to be rendered on the map which will update the appearance of the route line or an error. Note that an error will be returned in case no routes had been set to MapboxRouteLineApi prior to this invocation.
Parameters
offset
a value representing the percentage of the distance traveled along the route