lib/buffer-util.js
function _unmask(buffer, mask) {
  // Required until https://github.com/nodejs/node/issues/9006 is resolved.
  const length = buffer.length;
  for (let i = 0; i < length; i++) {
    buffer[i] ^= mask[i & 3];
  }
}
function _unmask(buffer, mask) {
  // Required until https://github.com/nodejs/node/issues/9006 is resolved.
  const length = buffer.length;
  for (let i = 0; i < length; i++) {
    buffer[i] ^= mask[i & 3];
  }
}
function _unmask ( buffer , mask ) { // Required until https://github.com/nodejs/node/issues/9006 is resolved. const length = buffer . length ; for ( let i = 0 ; i < length ; i ++ ) { buffer [ i ] ^= mask [ i & 3 ] ; } }
Unmasks a buffer using the given mask.

@param {Buffer} buffer The buffer to unmask
@param {Buffer} mask The mask to use
@public
Unmasks a buffer using the given mask .