<PackageReference Include="System.Formats.Asn1" Version="11.0.0-preview.6.26359.118" />

System.StringPolyfills

static class StringPolyfills
Provides downlevel polyfills for string extension methods.
namespace System { internal static class StringPolyfills { public static bool StartsWith(this string s, char value); public static bool EndsWith(this string s, char value); public static bool Contains(this string s, char value); } } namespace System { internal static class MemoryExtensionsPolyfills { public static bool Contains<T>(this ReadOnlySpan<T> span, T value) where T : IEquatable<T>; public static bool ContainsAnyExcept(this ReadOnlySpan<char> span, char value); public static bool ContainsAny(this ReadOnlySpan<char> span, ReadOnlySpan<char> values); } }