More Effective Coroutines [PRO]

Why performance differs

Unity's default coroutines allocate on every yield return, and the garbage collection that follows is what surfaces as stutter and hitching in a project that otherwise runs clean. MEC removes that per-yield allocation, so a scene running hundreds of coroutines does not accumulate collection debt over time. Throughput is roughly twice Unity's implementation.

Timing segments

Update, FixedUpdate, LateUpdate, SlowUpdate, RealtimeUpdate, EditorUpdate, EditorSlowUpdate, EndOfFrame and ManualTimeframe. The segment scheduler decides when each coroutine resumes, and SlowUpdate is the performance lever most projects reach for first: logic that does not need to run every frame moves to a relaxed tick and stops competing for frame budget. EditorUpdate and EditorSlowUpdate run coroutines in edit mode. SwitchCoroutine moves a running coroutine between segments or tags without restarting it.

Handles, tags and groups

Every coroutine returns a handle you can pause, resume, kill, re-tag, move between layers, or switch segments on. Tags and layers group coroutines so a whole set pauses or terminates together, which pauses every gameplay coroutine while a menu is open at no per-object performance cost. RunCoroutineSingleton enforces singleton behaviour for a coroutine, guaranteeing only one instance runs at a time.

Extension methods

Delay defers the start by a number of seconds. Append and Prepend chain one coroutine onto the next. CancelWith ends a coroutine when a given object goes out of scope, removing the usual null-check bookkeeping. Superimpose runs two together. Hijack rewrites a coroutine's return value, so identical logic can run in slow motion without a second implementation.

Compatibility and debugging

No MonoBehaviour inheritance required; any class can run a coroutine. MEC ships as source with no pre-compiled DLLs, so the profiler and debugger step straight into it and performance work is measurement rather than guesswork. MEC coroutines and Unity's own run side by side in one project, so migrating an existing codebase can be incremental. WaitForSeconds and the standard yield instructions have MEC equivalents that wait the same number of seconds without allocating.

Where the difference shows

The performance gap is widest in projects with many short-lived coroutines, because per-yield allocation is what the collector eventually charges you for. Removing it flattens the sawtooth in the memory graph. On a scene with a thousand active coroutines the difference is visible in the profiler rather than theoretical, which is the only kind of performance claim worth making.

Free and Pro

Both editions share the same core, so the baseline performance is identical. Pro adds the RealtimeUpdate, EditorUpdate, EditorSlowUpdate, EndOfFrame and ManualTimeframe segments, the singleton and SwitchCoroutine functions, every extension method above, and the full set of handle controls.