Example of Ruby class attribute to store BGThreadPool metrics

class_attributes_example.rb

class BGThreadPoolT
  # class attribute to store BGThreadPool metrics
  class_attribute :metrics
  # @note don't set this in code, it should only be set once on load
  # setting it again will result in loss of metrics
  self.metrics = Concurrent::Array.new
  def add_things
    self.class.metrics << "test #{self.object_id}"
    return nil
  end
end

b1 = BGThreadPoolT.new
b1.add_things
b2 = BGThreadPoolT.new
b2.add_things
b2.add_things
b2.add_things

ap BGThreadPoolT.metrics