This is a progress object specific to the current leg the user is on. If there is only one leg in the directions route, much of this information will be identical to the parent RouteProgress.
The latest route leg progress object can be obtained through the RouteProgressObserver. Note that the route leg progress object's immutable.
Index representing the current leg the user is on. If the directions route currently in use contains more then two waypoints, the route is likely to have multiple legs representing the distance between the two points.
Total distance traveled in meters along current leg
The distance remaining in meters until the user reaches the end of the leg
The duration remaining in seconds until the user reaches the end of the current step
The fraction traveled along the current leg, this is a float value between 0 and 1 and isn't guaranteed to reach 1 before the user reaches the next waypoint
Next/upcoming step immediately after the current step. If the user is on the last step on the last leg, this will return null since a next step doesn't exist