code: private boolean reachEndRange() {
          // current row key
          ByteBuffer rowKey;
  
          if (keyValidator instanceof CompositeType) {
              ByteBuffer[] keys = new ByteBuffer[partitionBoundColumns.size()];
              for (int i = 0; i < partitionBoundColumns.size(); i++) {
                  keys[i] = partitionBoundColumns.get(i).value.duplicate();
              }
  
              rowKey = CompositeType.build(keys);
          } else {
              rowKey = partitionBoundColumns.get(0).value;
          }
  
          String endToken = String.valueOf(split.getEndToken());
          String currentToken = partitioner.getToken(rowKey).toString();
  
          return endToken.equals(currentToken);
      }
docs: check whether current row is at the end of range
  
  @return the boolean