BenchmarkDotNet=v0.12.1, OS=Windows 10.0.18363.836 (1909/November2018Update/19H2)
Intel Core i7-8565U CPU 1.80GHz (Whiskey Lake), 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=3.1.302
  [Host]     : .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT
  DefaultJob : .NET Core 3.1.6 (CoreCLR 4.700.20.26901, CoreFX 4.700.20.31603), X64 RyuJIT

Method	Mean	Error	Median	Ratio	RatioSD	Gen 0	Allocated
FormatarInt	276.86 ns	7.559 ns	270.26 ns	1.00	0.00	0.0134	56 B
FormatarSubstring	156.32 ns	12.081 ns	143.49 ns	0.58	0.14	0.0629	264 B
FormatarStringBuilder	74.71 ns	1.460 ns	73.64 ns	0.27	0.02	0.0381	160 B
FormatarInsert	67.66 ns	5.311 ns	62.14 ns	0.24	0.06	0.0362	152 B
FormatarSpan	30.26 ns	1.597 ns	28.78 ns	0.11	0.02	0.0134	56 B