docs: public static TextProtocolBackendHandler newInstance(final String sql, final BackendConnection backendConnection) {
          if (sql.toUpperCase().startsWith(SCTL_SET)) {
              return new ShardingCTLSetBackendHandler(sql, backendConnection);
          }
          if (sql.toUpperCase().startsWith(SCTL_SHOW)) {
              return new ShardingCTLShowBackendHandler(sql, backendConnection);
          }
          if (sql.toUpperCase().startsWith(SCTL_EXPLAIN)) {
              return new ShardingCTLExplainBackendHandler(sql, backendConnection);
          }
          throw new IllegalArgumentException(sql);
      }