def call(name, input)
      fetch(name).call(Request.new(name, env, input))
    end
def call(name, input)
      fetch(name).call(Request.new(name, env, input))
    end
Invoke the action identified by +name+

 @example

   module App
     class Environment
       def initialize(storage, logger)
         @storage, @logger = storage, logger
       end
     end

     class SomeUseCase
       def self.call(request)
         data = perform_work
         request.success(data)
       end
     end
   end

   storage    = SomeStorageAbstraction.new
   env        = App::Environment.new(storage, Logger.new($stdout))
   config     = { :some_use_case => { :action => App::SomeUseCase } }
   dispatcher = Substation::Dispatcher.coerce(config, env)

   response = dispatcher.call(:some_use_case, :some_input)
   response.success? # => true

 @param [Symbol] name
   a registered action name

 @param [Object] input
   the input model instance to pass to the action

 @return [Response]
   the response returned when calling the action

 @raise [UnknownActionError]
   if no action is registered for +name+

 @api public