docs: private static Object decodeNextColumn(ByteBuffer bb, VoltType columnType)
              throws IOException {
          Object retval = null;
          switch (columnType) {
          case TINYINT:
              retval = decodeTinyInt(bb);
              break;
          case SMALLINT:
              retval = decodeSmallInt(bb);
              break;
          case INTEGER:
              retval = decodeInteger(bb);
              break;
          case BIGINT:
              retval = decodeBigInt(bb);
              break;
          case FLOAT:
              retval = decodeFloat(bb);
              break;
          case TIMESTAMP:
              retval = decodeTimestamp(bb);
              break;
          case STRING:
              retval = decodeString(bb);
              break;
          case VARBINARY:
              retval = decodeVarbinary(bb);
              break;
          case DECIMAL:
              retval = decodeDecimal(bb);
              break;
          case GEOGRAPHY_POINT:
              retval = decodeGeographyPoint(bb);
              break;
          case GEOGRAPHY:
              retval = decodeGeography(bb);
              break;
          default:
              throw new IOException("Invalid column type: " + columnType);
          }
  
          return retval;
      }