Here I'm drawing a line on the canvas guarding the mouse down (start to draw) mousemove (redraw line) and mouseup (end of draw phase).
How can I obtain the same offect using RXJS? In the example I found the draw phase happens on pace while the mouse is moving. Here I need to trigger the draw on the "mousedown", then save somehow the state of where I was starting drawing the line
and moving, and go on with the update phase until I raise the button up.