static equal(a, b, compareFn) {
    if (a === b) {
      return true;
    }
    if (!a || !b) {
      return a == b;
    }
    if (!compareFn) {
      compareFn = shaka.util.ArrayUtils.defaultEquals;
    }
    if (a.length != b.length) {
      return false;
    }

    for (let i = 0; i < a.length; i++) {
      if (!compareFn(a[i], b[i])) {
        return false;
      }
    }
    return true;
  }
Determines if the given arrays contain equal elements in the same order.

@param {Array<T>} a
@param {Array<T>} b
@param {function(T, T):boolean=} compareFn
@return {boolean}
@template T