<PackageReference Include="Microsoft.Extensions.Primitives" Version="10.0.5" />

Microsoft.Extensions.Primitives.InplaceStringBuilder

public struct InplaceStringBuilder
Provides a mechanism for fast, non-allocating string concatenation.
namespace Microsoft.Extensions.Primitives { public struct InplaceStringBuilder { public int Capacity { get; set; } public InplaceStringBuilder(int capacity); public void Append(string value); public void Append(StringSegment segment); public void Append(string value, int offset, int count); public void Append(char c); } }