class Bundler::Persistent::Net::HTTP::Persistent::Pool

def checkin net_http_args
  stack = Thread.current[@key][net_http_args] ||= []
  raise Bundler::ConnectionPool::Error, 'no connections are checked out' if
    stack.empty?
  conn = stack.pop
  if stack.empty?
    @available.push conn, connection_args: net_http_args
    Thread.current[@key].delete(net_http_args)
    Thread.current[@key] = nil if Thread.current[@key].empty?
  end
  nil
end

def checkout net_http_args
  stacks = Thread.current[@key] ||= {}
  stack  = stacks[net_http_args] ||= []
  if stack.empty? then
    conn = @available.pop connection_args: net_http_args
  else
    conn = stack.last
  end
  stack.push conn
  conn
end

def initialize(options = {}, &block)
  super
  @available = Bundler::Persistent::Net::HTTP::Persistent::TimedStackMulti.new(@size, &block)
  @key = "current-#{@available.object_id}"
end

def shutdown
  Thread.current[@key] = nil
  super
end