return bytealg.Index(s, sep)
		}
		c0 := sep[0]
		c1 := sep[1]
		i := 0
		t := len(s) - n + 1
		fails := 0
		for i < t {
			if s[i] != c0 {
				// IndexByte is faster than bytealg.Index, so use it as long as
				// we're not getting lots of false positives.
				o := IndexByte(s[i+1:t], c0)
				if o < 0 {
					return -1
				}
				i += o + 1
			}

	//
	// by the DECLARE_HANDLE macro in STRICT mode. The macro is declared in
	// the Windows ntdef.h header,
	//
	// https://github.com/tpn/winsdk-10/blob/master/Include/10.0.16299.0/shared/ntdef.h#L779
	if goos != "windows" {
		return false
	}
	if len(dt.Field) != 1 {
		return false
	}
	if dt.StructName != name+"__" {
		return false
	}

			// walking the tree and copying it piecewise. If the directory tree
			// contains nested modules this could push a lot of unnecessary contents,
			// but for the golang.org/x repos it seems to be significantly (~2x)
			// faster than copying one file at a time (via filepath.WalkDir),
			// apparently due to high latency in 'adb' commands.
			if err := adb("push", modDir, deviceModDir); err != nil {
				return 0, err
			}
		} else {