úÎ!8E7 None]iz timer-wheelAn empty collection. timer-wheel'The number of timers in the collection. timer-wheelinsert i n m x inserts callback m into collection x with unique identifier i and "count" n. The timer-wheelDelete a timer by id. Returns   if the timer was not found.  timer-wheelExtract expired timers.   NoneÍ None $%DLV]6Ý  timer-wheelA H is a vector-of-collections-of timers to fire. It is configured with a  spoke count and  resolutionl. A timeout thread is spawned to step through the timer wheel and fire expired timers at regular intervals.The  spoke count) determines the size of the timer vector.A larger spoke count will result in less insert contention" at each spoke and will require  more memory to store the timer wheel.A smaller spoke count will result in more insert contention" at each spoke and will require  less memory to store the timer wheel.The  resolution– determines both the duration of time that each spoke corresponds to, and how often the timeout thread wakes. For example, with a resolution of 1s, a timer that expires at 2.5s4 will not fire until the timeout thread wakes at 3s.A larger resolution will result in more insert contention at each spoke,  less accurate timers, and will require  fewer wakeups by the timeout thread.A smaller resolution will result in less insert contention at each spoke,  more accurate timers, and will require  more wakeups by the timeout thread.2The timeout thread has three important properties:fThere is only one, and it fires expired timers synchronously. If your timer actions execute quicky, N them directly. Otherwise, consider registering an action that enqueues the real) action to be performed on a job queue.*Synchronous exceptions thrown by enqueued IOË actions will bring the thread down, and no more timeouts will ever fire. If you want to catch exceptions and log them, for example, you will have to bake this into the registered actions yourself.ÂThe life of the timeout thread is scoped to the life of the timer wheel. When the timer wheel is garbage collected, the timeout thread will automatically stop doing work, and die gracefully.+Below is a depiction of a timer wheel with 6 timers inserted across 8 spokes, and a resolution of 0.1s. Õ 0s .1s .2s .3s .4s .5s .6s .7s .8s +-----+-----+-----+-----+-----+-----+-----+-----+ | | A | | B,C | D | | | E,F | +-----+-----+-----+-----+-----+-----+-----+-----+  timer-wheelBThe length of time that each entry corresponds to, in nanoseconds. timer-wheelA supply of unique ints. timer-wheel#The array of collections of timers. timer-wheelnew n s creates a  with n spokes and a resolution of s seconds. timer-wheelregister n m w registers an action m in timer wheel w to fire after n seconds.rReturns an action that, when called, attempts to cancel the timer, and returns whether or not it was successful (False% means the timer has already fired). timer-wheelLike 4, but for when you don't intend to cancel the timer. timer-wheelrecurring n m w registers an action m in timer wheel w to fire every n seconds.AReturns an action that, when called, cancels the recurring timer. timer-wheelentriesIn delay wheel returns the bucket in wheel that corresponds to delay nanoseconds from now. timer-wheel%Repeat an IO action until it returns .    (timer-wheel-0.1.0-COcXKRM2lMF8Txyn5YGRIfData.TimerWheelEntriesSupply TimerWheelnewregister register_ recurringemptysizeinsertdeletebaseGHC.BaseNothingsquamnullnextwheelResolution wheelSupply wheelEntries entriesIn untilTrueghc-prim GHC.TypesTrue