focalPoint 
  Focal point that defines the position of the first framed geometry point (typically the user location indicator, if available) in the MapboxNavigationViewportDataSource.followingPadding.
The value is a horizontal and vertical ratio starting from the top left corner of the padding, in the <0.0, 1.0> range. Example:
- FocalPoint(0.0, 0.0)positions the first geometry point in the top left
- FocalPoint(0.5, 0.5)positions the first geometry point in the center
- FocalPoint(1.0, 1.0)positions the first geometry point in the bottom right
Defaults to FocalPoint(0.5, 1.0) that centers horizontally on the bottom edge of the padding.
NOTE: The focal point change has no effect when the camera's pitch is 0 and maximizeViewableGeometryWhenPitchZero is enabled.