[Feature]: Minimise allocations and hot‑path overhead

[eneshoxha]

Reuse Stopwatch instances or use Stopwatch.GetTimestamp – the code creates a new Stopwatch for every message, which allocates an object. The Stopwatch class is more precise and lightweight than DateTime.Now.
, but creating thousands of instances still incurs overhead. In hot paths, call Stopwatch.GetTimestamp() at the start and compute elapsed time using Stopwatch.GetElapsedTime to avoid allocation; or pool Stopwatch instances if precise measurement is necessary.

Cache delegates – the telemetry setup caches delegates for metrics recording, which is good. Similarly cache the input cast Func<object,T> or the key selector to avoid repeated boxing/unboxing in generic operators.

Avoid boxing in Process – currently operators take object input and cast to T. Using IOperator<T> with a generic Process(T input) avoids boxing and repeated type checks. This change would require making the pipeline generic, but will improve performance for value types.

Use List<T>.AddRange instead of iterative adds – when grouping, the code retrieves a list and calls Add on each element. If many elements are grouped at once (e.g., through FlatMap), using AddRange can reduce internal array resizing.