# File lib/faraday/connection.rb, line 143
    def in_parallel(manager = nil)
      @parallel_manager = manager || default_parallel_manager {
        warn "Warning: `in_parallel` called but no parallel-capable adapter on Faraday stack"
        warn caller[2,10].join("\n")
        nil
      }
      yield
      @parallel_manager && @parallel_manager.run
    ensure
      @parallel_manager = nil
    end