docs: private void removeBlockRequest(final Piece piece) {
      synchronized (this.requestsLock) {
        Integer requestedBlocksCount = myRequestedPieces.get(piece);
        if (requestedBlocksCount == null) {
          return;
        }
        if (requestedBlocksCount <= 1) {
          //it's last block
          myRequestedPieces.remove(piece);
        } else {
          myRequestedPieces.put(piece, requestedBlocksCount - 1);
        }
        this.downloading = myRequestedPieces.size() > 0;
      }
    }