class ActiveSupport::Notifications::Event

def <<(event)
  @children << event
end

def duration
  @duration ||= 1000.0 * (self.end - time)
end

def initialize(name, start, ending, transaction_id, payload)
  @name           = name
  @payload        = payload.dup
  @time           = start
  @transaction_id = transaction_id
  @end            = ending
  @children       = []
  @duration       = nil
end

def parent_of?(event)
  @children.include? event
end