code: func (q *Quadtree) InBound(b *geo.Bound, buf ...[]geo.Pointer) []geo.Pointer {
  	return q.InBoundMatching(b, nil, buf...)
  }
docs: // InBound returns a slice with all the pointers in the quadtree that are
  // within the given bound. An optional buffer parameter is provided to allow
  // for the reuse of result slice memory. This function is thread safe.
  // Multiple goroutines can read from a pre-created tree.