code: public boolean contains(Object objectToCheck, int hash) {
          checkNotNull(objectToCheck);
  
          int index = hash & mask;
  
          // using the hashes array for looping and comparison if possible, hence we're cache friendly
          while (hashes[index] != 0 || table[index] != null) {
              if (hash == hashes[index] && objectToCheck.equals(table[index])) {
                  return true;
              }
              index = ++index & mask;
          }
  
          return false;
      }
docs: Returns <tt>true</tt> if this set contains the specified element
  with the hash provided in parameter.
  <p>
  This variant of {@link #contains(Object)} acts as an optimisation to
  enable avoiding {@link #hashCode()} calls if the hash is already
  known on the caller side.
  
  @param objectToCheck element whose presence in this set is to be tested
  @param hash          the hash of the element to be tested
  @return <tt>true</tt> if this set contains the specified element
  @see #contains(Object)