--- Applies the given brush with the given height and size to the given position.
-- @param pos1 Vector3 The position at which to apply the brush.
-- @param brush_name string The name of the brush to apply.
-- @param height number The height of the brush application.
-- @param brush_size Vector3 The size of the brush application. Values are interpreted on the X/Y coordinates, and NOT X/Z!
-- @returns bool, string|{ added: number, removed: number } A bool indicating whether the operation was successful or not, followed by either an error message as a string (if it was not successful) or a table of statistics (if it was successful).