def error_flow=(error_flow)
      unless error_flow.nil? || error_flow.is_a?(Rackstash::Flow)
        error_flow = Flow.new(error_flow)
      end

      @error_flow = error_flow
    end
def error_flow=(error_flow)
      unless error_flow.nil? || error_flow.is_a?(Rackstash::Flow)
        error_flow = Flow.new(error_flow)
      end

      @error_flow = error_flow
    end
Set a separate {Flow} which is used by this flow to write details
 about any unexpected errors during interaction with the {#adapter}.

 If the given object is not already a {Flow}, we will wrap in into one.
 This allows you to also give an adapter or just a plain log target which
 can be wrapped in an adapter.

 When setting the `error_flow` to nil, we reset any custom `error_flow` on
 this current Flow and will use the global {Rackstash.error_flow} to log
 any errors.

 @param error_flow [Flow, Adapter, Object, nil] the separate error flow or
   `nil` to unset the custom error_flow and to use the global
   {Rackstash.error_flow} again
 @return [Rackstash::Flow] the newly set error_flow