AsyncUtils
public static Task<int> ReadAsync(this TextReader reader, char[] buffer, int index, int count, CancellationToken cancellationToken)
public static Task WriteAsync(this TextWriter writer, char value, CancellationToken cancellationToken)
public static Task WriteAsync(this TextWriter writer, string value, CancellationToken cancellationToken)
public static Task WriteAsync(this TextWriter writer, char[] value, int start, int count, CancellationToken cancellationToken)