docs: public final byte[] getVarbinary(int columnIndex) {
          validateColumnType(columnIndex, VoltType.VARBINARY);
          int pos = m_buffer.position();
          m_buffer.position(getOffset(columnIndex));
          // Sanity check the varbinary size int position.
          if (VARBINARY_LEN_SIZE > m_buffer.remaining()) {
              throw new RuntimeException(String.format(
                      "VoltTableRow::getVarbinary: Can't read varbinary size as %d byte integer " +
                      "from buffer with %d bytes remaining.",
                      VARBINARY_LEN_SIZE, m_buffer.remaining()));
          }
          int len = m_buffer.getInt();
          if (len == VoltTable.NULL_STRING_INDICATOR) {
              m_wasNull = true;
              m_buffer.position(pos);
              return null;
          }
          // Sanity check the size against the remaining buffer size.
          if (len > m_buffer.remaining()) {
              throw new RuntimeException(String.format(
                      "VoltTableRow::getVarbinary: Can't read %d byte varbinary " +
                      "from buffer with %d bytes remaining.", len, m_buffer.remaining()));
          }
          m_wasNull = false;
          byte[] data = new byte[len];
          m_buffer.get(data);
          m_buffer.position(pos);
          return data;
      }