def with_all(continue_on_error = false)
      cluster.shards.map do |shard|
        begin
          with_shard(shard) {
            yield
          }
        rescue Exception => err
          unless continue_on_error
            raise err
          end
          err
        end
      end
    end
def with_all(continue_on_error = false)
      cluster.shards.map do |shard|
        begin
          with_shard(shard) {
            yield
          }
        rescue Exception => err
          unless continue_on_error
            raise err
          end
          err
        end
      end
    end
Send queries to all shards in this cluster
 @param [Boolean] continue_on_error when a shard raises error, ignore exception and continue