code: private static ByteBuffer trim(ByteBuffer buf) {
          if (buf.capacity() <= 4 * buf.remaining()) {
              return buf;
          } else {
              ByteBuffer clone = ByteBuffer.allocate(buf.remaining());
              buf.get(clone.array());
              return clone;
          }
      }
docs: Serialized Astyanax Composite objects use a lot of memory.  Trim it down.