# File lib/connection_pool.rb, line 44
  def initialize(options = {}, &block)
    raise ArgumentError, 'Connection pool requires a block' unless block

    options = DEFAULTS.merge(options)

    @size = options.fetch(:size)
    @timeout = options.fetch(:timeout)

    @available = TimedStack.new(@size, &block)
    @key = "current-#{@available.object_id}""current-#{@available.object_id}"
    @key_count = "current-#{@available.object_id}-count""current-#{@available.object_id}-count"
  end