class ActiveSupport::Notifications::Event

def allocations

the call to #finish!.
Returns the number of allocations made between the call to #start! and 
def allocations
  @allocation_count_finish - @allocation_count_start
end

def cpu_time

#start! and the call to #finish!.
Returns the CPU time (in milliseconds) passed between the call to 
def cpu_time
  @cpu_time_finish - @cpu_time_start
end

def duration

@event.duration # => 1000.138

end
sleep 1
ActiveSupport::Notifications.instrument('wait') do

end
@event = event
ActiveSupport::Notifications.subscribe('wait') do |event|

event started and when it ended.
Returns the difference in milliseconds between when the execution of the 
def duration
  @end - @time
end

def end 

def end
  @end / 1000.0 if @end
end

def finish!

Record information at the time this event finishes 
def finish!
  @cpu_time_finish = now_cpu
  @gc_time_finish = now_gc
  @end = now
  @allocation_count_finish = now_allocations
end

def gc_time

and the call to #finish!
Returns the time spent in GC (in milliseconds) between the call to #start! 
def gc_time
  (@gc_time_finish - @gc_time_start) / 1_000_000.0
end

def idle_time

#start! and the call to #finish!.
Returns the idle time time (in milliseconds) passed between the call to 
def idle_time
  diff = duration - cpu_time
  diff > 0.0 ? diff : 0.0
end

def initialize(name, start, ending, transaction_id, payload) 

def initialize(name, start, ending, transaction_id, payload)
  @name           = name
  @payload        = payload.dup
  @time           = start ? start.to_f * 1_000.0 : start
  @transaction_id = transaction_id
  @end            = ending ? ending.to_f * 1_000.0 : ending
  @cpu_time_start = 0.0
  @cpu_time_finish = 0.0
  @allocation_count_start = 0
  @allocation_count_finish = 0
  @gc_time_start = 0
  @gc_time_finish = 0
end

def now 

def now
  Process.clock_gettime(Process::CLOCK_MONOTONIC, :float_millisecond)
end

def now_allocations 

def now_allocations
  GC.stat(:total_allocated_objects)
end

def now_allocations

Likely on JRuby, TruffleRuby 
def now_allocations
  0
end

def now_cpu 

def now_cpu
  Process.clock_gettime(Process::CLOCK_THREAD_CPUTIME_ID, :float_millisecond)
end

def now_cpu 

def now_cpu
  0.0
end

def now_gc 

def now_gc
  GC.total_time
end

def now_gc 

def now_gc
  0
end

def record # :nodoc:

:nodoc: 
def record # :nodoc:
  start!
  begin
    yield payload if block_given?
  rescue Exception => e
    payload[:exception] = [e.class.name, e.message]
    payload[:exception_object] = e
    raise e
  ensure
    finish!
  end
end

def start!

Record information at the time this event starts 
def start!
  @time = now
  @cpu_time_start = now_cpu
  @gc_time_start = now_gc
  @allocation_count_start = now_allocations
end

def time 

def time
  @time / 1000.0 if @time
end