code: public Log release(long index) {
      assertIsOpen();
      assertValidIndex(index);
  
      Segment segment = segments.segment(index);
      Assert.index(segment != null, "invalid index: " + index);
      segment.release(index);
      return this;
    }
docs: Releases the entry at the given index.
  
  @param index The index of the entry to release.
  @return The log.
  @throws IllegalStateException If the log is not open.
  @throws IndexOutOfBoundsException If the given index is not within the bounds of the log.