StringCreator

Assembling a string with a pre-known resulting string length: uses 50% less memory then StringBuilder.

Benchmark:

Method	Job	Runtime	StrLength	Mean	Ratio	Allocated	Alloc Ratio
StringBuilder	.NET 10.0	.NET 10.0	5	36.88 ns	1.00	120 B	1.00
DefaultInterpolatedStringHandler	.NET 10.0	.NET 10.0	5	149.72 ns	4.07	152 B	1.27
Concatenation	.NET 10.0	.NET 10.0	5	108.69 ns	2.95	248 B	2.07
StringCreator	.NET 10.0	.NET 10.0	5	27.45 ns	0.75	64 B	0.53
StringBuilder	NativeAOT 10.0	NativeAOT 10.0	5	40.36 ns	1.00	120 B	1.00
DefaultInterpolatedStringHandler	NativeAOT 10.0	NativeAOT 10.0	5	176.95 ns	4.40	152 B	1.27
Concatenation	NativeAOT 10.0	NativeAOT 10.0	5	145.19 ns	3.61	248 B	2.07
StringCreator	NativeAOT 10.0	NativeAOT 10.0	5	37.59 ns	0.93	64 B	0.53
StringBuilder	.NET 10.0	.NET 10.0	25	112.02 ns	1.00	200 B	1.00
DefaultInterpolatedStringHandler	.NET 10.0	.NET 10.0	25	531.40 ns	4.74	672 B	3.36
Concatenation	.NET 10.0	.NET 10.0	25	623.67 ns	5.57	1848 B	9.24
StringCreator	.NET 10.0	.NET 10.0	25	104.48 ns	0.93	104 B	0.52
StringBuilder	NativeAOT 10.0	NativeAOT 10.0	25	144.13 ns	1.00	200 B	1.00
DefaultInterpolatedStringHandler	NativeAOT 10.0	NativeAOT 10.0	25	616.37 ns	4.28	672 B	3.36
Concatenation	NativeAOT 10.0	NativeAOT 10.0	25	817.48 ns	5.67	1848 B	9.24
StringCreator	NativeAOT 10.0	NativeAOT 10.0	25	149.63 ns	1.04	104 B	0.52
StringBuilder	.NET 10.0	.NET 10.0	100	406.36 ns	1.00	496 B	1.00
DefaultInterpolatedStringHandler	.NET 10.0	.NET 10.0	100	1,949.56 ns	4.80	2624 B	5.29
Concatenation	.NET 10.0	.NET 10.0	100	2,744.22 ns	6.75	14976 B	30.19
StringCreator	.NET 10.0	.NET 10.0	100	392.47 ns	0.97	256 B	0.52
StringBuilder	NativeAOT 10.0	NativeAOT 10.0	100	530.65 ns	1.00	496 B	1.00
DefaultInterpolatedStringHandler	NativeAOT 10.0	NativeAOT 10.0	100	2,378.89 ns	4.49	2624 B	5.29
Concatenation	NativeAOT 10.0	NativeAOT 10.0	100	3,869.99 ns	7.30	14976 B	30.19
StringCreator	NativeAOT 10.0	NativeAOT 10.0	100	562.36 ns	1.06	256 B	0.52
StringBuilder	.NET 10.0	.NET 10.0	1000	3,891.79 ns	1.00	4096 B	1.00
DefaultInterpolatedStringHandler	.NET 10.0	.NET 10.0	1000	19,318.02 ns	4.96	26024 B	6.35
Concatenation	.NET 10.0	.NET 10.0	1000	63,794.51 ns	16.39	1049976 B	256.34
StringCreator	.NET 10.0	.NET 10.0	1000	3,693.73 ns	0.95	2056 B	0.50
StringBuilder	NativeAOT 10.0	NativeAOT 10.0	1000	5,190.07 ns	1.00	4096 B	1.00
DefaultInterpolatedStringHandler	NativeAOT 10.0	NativeAOT 10.0	1000	23,148.44 ns	4.47	26024 B	6.35
Concatenation	NativeAOT 10.0	NativeAOT 10.0	1000	72,140.25 ns	13.95	1049976 B	256.34
StringCreator	NativeAOT 10.0	NativeAOT 10.0	1000	5,201.16 ns	1.01	2056 B	0.50

Usage:

            var stringCreator = new StringCreator.Class.StringCreator(50);
            for (int i = 0; i < 50; i++)
            {
                stringCreator.Append($"{i % 10}");
            }

            var result = stringCreator.ToString();