code: public final boolean containsEntry(Object key, Object value) {
          long hash, allocIndex;
          Segment<K, V> segment;
          V v;
          return (allocIndex = (segment = segment(segmentIndex(hash = keyHashCode(key))))
                  .find(this, hash, key)) > 0 &&
                  ((v = segment.readValue(allocIndex)) == value ||
                          (value != null && valuesEqual(value, v)));
      }
docs: Returns {@code true} if this map contains a mapping of the given key and value. More
  formally, this map should contain a mapping from a key {@code k} to a value {@code v} such
  that {@link #keysEqual(Object, Object) keysEqual(key, k)}{@code == true} and {@link
  #valuesEqual(Object, Object) valuesEqual(value, v)}{@code == true}. (There can be at most one
  such mapping.)
  
  @param key the key of the mapping to check presence of
  @param value the value of the mapping to check presence of
  @return {@code true} if this map contains the specified mapping, {@code false} otherwise