Lag: IList<> implementation

[viceroypenguin]

This PR adds an IList<> implementation of Lag, which reduces memory usage and improves performance.

Fixes #403

// * Summary *

BenchmarkDotNet=v0.13.5, OS=Windows 11 (10.0.22621.1555/22H2/2022Update/SunValley2)
12th Gen Intel Core i7-12700H, 1 CPU, 20 logical and 14 physical cores
.NET SDK=8.0.100-preview.3.23178.7
  [Host] : .NET 7.0.5 (7.0.523.17405), X64 RyuJIT AVX2

Method	source	N	Mean	Error	StdDev	Gen0	Gen1	Allocated
LagCount	Syste(...)nt32] [47]	10000	9.776 ns	0.1670 ns	0.1394 ns	0.0032	0.0000	40 B
LagCount	Syste(...)nt32] [62]	10000	127,925.439 ns	925.8349 ns	773.1141 ns	-	-	464 B
LagCopyTo	Syste(...)nt32] [47]	10000	84,319.089 ns	448.5254 ns	419.5509 ns	6.3477	1.0986	80112 B
LagCopyTo	Syste(...)nt32] [62]	10000	159,364.525 ns	3,112.8400 ns	3,057.2251 ns	16.8457	2.9297	212200 B
LagElementAt	Syste(...)nt32] [47]	10000	16.877 ns	0.0723 ns	0.0641 ns	0.0032	0.0000	40 B
LagElementAt	Syste(...)nt32] [62]	10000	101,622.887 ns	906.5200 ns	847.9594 ns	-	-	464 B

Code

#load "BenchmarkDotNet"

void Main()
{
	RunBenchmark();
}

public IEnumerable<object[]> EnumerableArguments()
{
	foreach (var i in new[] { 10_000, })
	{
		yield return new object[]
		{
			Enumerable.Range(1, i).Where(_ => true),
			i,
		};
		yield return new object[]
		{
			Enumerable.Range(1, i).ToList(),
			i,
		};
	}
}

[Benchmark]
[ArgumentsSource(nameof(EnumerableArguments))]
public void LagCount(IEnumerable<int> source, int N)
{
	_ = source.Lag(50).Count();
}

[Benchmark]
[ArgumentsSource(nameof(EnumerableArguments))]
public void LagCopyTo(IEnumerable<int> source, int N)
{
	_ = source.Lag(50).ToArray();
}

[Benchmark]
[ArgumentsSource(nameof(EnumerableArguments))]
public void LagElementAt(IEnumerable<int> source, int N)
{
	_ = source.Lag(50).ElementAt(8_000);
}

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.04 🎉

Comparison is base (8552236) 87.72% compared to head (dee4505) 87.77%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #404      +/-   ##
==========================================
+ Coverage   87.72%   87.77%   +0.04%     
==========================================
  Files         239      239              
  Lines        7357     7370      +13     
  Branches     1701     1702       +1     
==========================================
+ Hits         6454     6469      +15     
+ Misses        463      461       -2     
  Partials      440      440              

Impacted Files	Coverage Δ
Source/SuperLinq/Lag.cs	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

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