DetectEncodingAsync

Asynchronously detects text encoding from a stream by checking BOM, binary heuristics, and fallback analysis, resetting stream position after.

    public static async Task<Encoding?> DetectEncodingAsync(Stream stream, int bufferSize = 4096, CancellationToken cancellationToken = default)
    {
        if (!stream.CanRead) throw new ArgumentException("Stream must be readable.", nameof(stream));
        if (!stream.CanSeek) throw new ArgumentException("Stream must be seekable.", nameof(stream));

        var originalPosition = stream.Position;
        stream.Seek(0, SeekOrigin.Begin);

        var buffer = ArrayPool<byte>.Shared.Rent(bufferSize);

        try
        {
            // ReadAtLeastAsync ensures we fill the buffer if possible, reducing partial read issues.
            var bytesRead = await stream.ReadAtLeastAsync(buffer.AsMemory(0, bufferSize), bufferSize, throwOnEndOfStream: false, cancellationToken: cancellationToken)

... (truncated -- full source via MCP)