3.3.0

• Simulation of String.Create(int, TState, SpanAction<char, TState>) that works also for
  older .NET Versions:

string StringCreator.Create<TState>(int, TState, SpanAction<char, TState>);

.

• New extension methods for the Char structure:

bool IsAsciiLowerCaseLetter(this char);
bool IsAsciiUpperCaseLetter(this char);
bool IsAsciiLetter(this char);

.

• New extension method for the ReadOnlySpan<Char> structure:

int LastIndexOf(this ReadOnlySpan<char>, ReadOnlySpan<char>, int, int, StringComparison);

.

• New polyfills for .NET Framework 4.5 and .NET Standard 2.0:

int LastIndexOf(this ReadOnlySpan<char>, string?, StringComparison);
int LastIndexOf(this ReadOnlySpan<char>, string?, int, int, StringComparison);

System.Buffers.SpanAction<T, TArg>;

.

• New polyfill for .NET Framework 4.5, .NET Standard 2.0 and .NET Standard 2.1:

int LastIndexOf(this ReadOnlySpan<char>, ReadOnlySpan<char>, StringComparison);