const compress/flate.windowMask

5 uses

	compress/flate (current package)
		deflate.go#L35: 	windowMask    = windowSize - 1
		deflate.go#L219: 			d.hashPrev[di&windowMask] = *hh
		deflate.go#L275: 		i = int(d.hashPrev[i&windowMask]) - d.hashOffset
		deflate.go#L422: 			d.hashPrev[d.index&windowMask] = uint32(d.chainHead)
		deflate.go#L469: 						d.hashPrev[index&windowMask] = *hh