(PECL ev >= 0.2.0)
EvTimer watchers are simple relative timers that generate an event after a given time, and optionally repeating in regular intervals after that.
The timers are based on real time, that is, if one registers an event that times out after an hour and resets the system clock to January last year , it will still time out after(roughly) one hour. "Roughly" because detecting time jumps is hard, and some inaccuracies are unavoidable.
The callback is guaranteed to be invoked only after its timeout has passed (not at, so on systems with very low-resolution clocks this might introduce a small delay). If multiple timers become ready during the same loop iteration then the ones with earlier time-out values are invoked before ones of the same priority with later time-out values (but this is no longer true when a callback calls EvLoop::run() recursively).
    The timer itself will do a best-effort at avoiding drift, that is, if a
    timer is configured to trigger every
    10
    seconds, then it will normally trigger at exactly
    10
    second intervals. If, however, the script cannot keep up with the timer
    because it takes longer than those
    10
    seconds to do) the timer will not fire more than once per event loop
    iteration.
   
$after
   
   , 
    double
     $repeat
   
   , 
    callable
     $callback
   
   [, 
    mixed
     $data
     = NULL
   
   [, 
    int
     $priority
     = 0
   
  ]] )$after
   
   , 
    double
     $repeat
   
   , 
    callable
     $callback
   
   [, 
    mixed
     $data
     = NULL
   
   [, 
    int
     $priority
     = 0
   
  ]] )
       If repeat is
       0.0
       , then it will automatically be stopped once the timeout is reached. If
       it is positive, then the timer will automatically be configured to
       trigger again every repeat seconds later, until stopped manually.
      
Returns the remaining time until a timer fires. If the timer is active, then this time is relative to the current event loop time, otherwise it's the timeout value currently configured.
       That is, after instanciating an
       EvTimer
       with an
       after
       value of
       5.0
       and
       repeat
       value of
       7.0
       ,
       remaining
       returns
       5.0
       . When the timer is started and one second passes,
       remaining
       will return
       4.0
       . When the timer expires and is restarted, it will return roughly
       7.0
       (likely slightly less as callback invocation takes some time too), and
       so on.