class Roda::RodaPlugins::MiddlewareStack::Stack

removing middleware or finding places to insert new middleware.
Represents the applications middleware as a stack, allowing for easily

def after(&block)

new middleware at the end of the stack.
It the block never returns true, returns a StackPosition that will insert
given, but not the middleware block.
the block returns true. Yields the middleware and any middleware arguments
Return a StackPosition representing the position after the middleware where 
def after(&block)
  handle(1, &block)
end

def before(&block)

new middleware at the end of the stack.
It the block never returns true, returns a StackPosition that will insert
given, but not the middleware block.
the block returns true. Yields the middleware and any middleware arguments
Return a StackPosition representing the position before the middleware where 
def before(&block)
  handle(0, &block)
end

def handle(offset)

Internals of before and after. 
def handle(offset)
  @middleware.each_with_index do |(m, _), i|
    if yield(*m)
      return StackPosition.new(@app, @middleware, i+offset)
    end
  end
  StackPosition.new(@app, @middleware, @middleware.length)
end

def initialize(app, middleware) 

def initialize(app, middleware)
  @app = app
  @middleware = middleware
end

def remove

and any middleware arguments given, but not the middleware block
Removes any middleware where the block returns true. Yields the middleware 
def remove
  @middleware.delete_if do |m, _|
    yield(*m)
  end
  @app.send(:build_rack_app)
  nil
end