docs: public static ApproximateHistogram fromBytes(ByteBuffer buf)
    {
      // negative size indicates compact representation
      // this works regardless of whether we use int or short for the size since the leftmost bit is the sign bit
      if (buf.getShort(buf.position()) < 0) {
        return fromBytesCompact(buf);
      } else {
        // ignore size, determine if sparse or dense based on sign of binCount
        if (buf.getInt(buf.position() + Integer.BYTES) < 0) {
          return fromBytesSparse(buf);
        } else {
          return fromBytesDense(buf);
        }
      }
    }