Adds an arrow to the plot. The arrow is drawn from `(x1, y1)` to `(x2, y2)` with the arrow point towards `(x2, y2)`. # Arguments `x1` - X coordinate of the arrow start `y1` - Y coordinate of the arrow start `x2` - X coordinate of the arrow end `y2` - Y coordinate of the arrow end `options` - Array of PlotOption<&str> controlling the appearance of the arrowhead and arrow shaft. Relevant options are
( &'l mut self, x1: Coordinate, y1: Coordinate, x2: Coordinate, y2: Coordinate, options: &[PlotOption<&str>], )
source not stored for this graph (policy: none)
no test coverage detected