Add a more aggressive fast-path for Invoke(object[])

[WAcry]

Stack

• Prerequisite: #371 -> This PR: #372

#372 currently contains all commits from #371 plus one extra commit.

What & why

Invoke(object[]) is a common hot path. Even after #371, the fallback path still pays for:

• building usedArgs (when declared != used), and/or
• DynamicInvoke overhead.

This PR introduces an additional fast-path that, when applicable, bypasses both costs.

Changes

• Add a more aggressive Invoke(object[]) fast-path:
  • In Lambda’s internal InvocationContext, compile once a Func<object[], object> “fast invoker”.
  • When the declared argument array passed to Invoke(object[]) meets the type assignability / nullable-compatibility constraints, invoke via the fast invoker:
    • Avoids DynamicInvoke
    • Avoids constructing usedArgs
  • Otherwise, fall back to the safe path:
    • build usedArgs + DynamicInvoke

Benchmark results

Environment:

• BenchmarkDotNet v0.14.0
• Windows 11 (10.0.26200.7705)
• 11th Gen Intel Core i7-11800H (16 logical / 8 physical)
• .NET 8.0.23 (x64 RyuJIT)
• .NET SDK 10.0.102

Raw numbers

Method	master Mean (ms)	PR #371 Mean (ms)	PR #372 Mean (ms)	master Alloc (MB)	PR #371 Alloc (MB)	PR #372 Alloc (MB)
Invoke cached lambda (object[])	221.70	10.04	2.867	260.93	9.16	2.29
Invoke cached lambda (IEnumerable<Parameter>)	175.80	96.20	97.169	191.50	37.38	37.38
Eval (IEnumerable<Parameter>)	25,503.70	16,346.04	16,821.122	17,172.52	16,800.18	16,781.66

Derived comparisons

Method	master → #371 speedup	master → #372 speedup	#371 → #372 speedup	master → #371 alloc reduction	master → #372 alloc reduction	#371 → #372 alloc reduction
Invoke cached lambda (object[])	22.08x	77.31x	3.50x	28.49x	113.94x	4.00x
Invoke cached lambda (IEnumerable<Parameter>)	1.83x	1.81x	0.99x	5.12x	5.12x	1.00x
Eval (IEnumerable<Parameter>)	1.56x	1.52x	0.97x	1.02x	1.02x	1.00x

Notes:

• PR #372 delivers an additional big win for Invoke(object[]):
  • vs PR #371: ~3.5x faster, ~4x fewer allocations
  • vs master: ~77x faster, ~114x fewer allocations
    (in this benchmark scenario)
• Invoke(IEnumerable<Parameter>) / Eval(...) are effectively unchanged from #371 — this fast-path is intentionally targeted at declared-order object[].