code: function distanceFromIntersectArea(r1, r2, overlap) {
          // handle complete overlapped circles
          if (Math.min(r1, r2) * Math.min(r1,r2) * Math.PI <= overlap + SMALL$1) {
              return Math.abs(r1 - r2);
          }
  
          return bisect(function(distance$$1) {
              return circleOverlap(r1, r2, distance$$1) - overlap;
          }, 0, r1 + r2);
      }
docs: Returns the distance necessary for two circles of radius r1 + r2 to
  have the overlap area 'overlap'