class RedisClient

def multi(watch: nil, &block)
  transaction = nil
  results = if watch
    # WATCH is stateful, so we can't reconnect if it's used, the whole transaction
    # has to be redone.
    ensure_connected(retryable: false) do |connection|
      call("WATCH", *watch)
      begin
        if transaction = build_transaction(&block)
          commands = transaction._commands
          results = @middlewares.call_pipelined(commands, config) do
            connection.call_pipelined(commands, nil)
          end.last
        else
          call("UNWATCH")
          []
        end
      rescue
        call("UNWATCH") if connected? && watch
        raise
      end
    end
  else
    transaction = build_transaction(&block)
    if transaction._empty?
      []
    else
      ensure_connected(retryable: transaction._retryable?) do |connection|
        commands = transaction._commands
        @middlewares.call_pipelined(commands, config) do
          connection.call_pipelined(commands, nil)
        end.last
      end
    end
  end
  if transaction
    transaction._coerce!(results)
  else
    results
  end
end