Please allow us to customize `OutputStream` and `ExtendedOutputStream` before executing an SSH command.

首先检查 SshCommand.OutputStream 和 ExtendedOutputStream、可扩展的 PipeStream 类型以及 ExecuteAsync 入口点。定义并验证一种公共自定义机制，在不使用反射的情况下支持实时处理标准输出和错误，同时确保两个流在命令执行期间仍可使用。

I have a use case where I want real time output from the console command to be printed to the console. Unfortunately, the streams that are written to cannot be customized with the existing public interface, even though the PipeStream class is extensible. The best solution I found to do what I need to do unfortunately requires reflection.

A public interface (such as a callback) for this feature would be greatly appreciated.

public static class SshClientExtensions
{
    public static async Task<SshCommand> ConnectAndExecuteCommandAsync(this SshClient client, string command, CancellationToken cancellationToken = default)
    {
        SshCommand sshCommand;
        try
        {
            await client.ConnectAsync(cancellationToken);
            sshCommand = client.CreateCommand(command);
            using CancellationTokenSource linkedCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);

            BindingFlags bindingFlags = BindingFlags.Public | BindingFlags.Instance;
            PropertyInfo stdOutProp = typeof(SshCommand).GetProperty(nameof(SshCommand.OutputStream), bindingFlags)!;
            PropertyInfo stdErrProp = typeof(SshCommand).GetProperty(nameof(SshCommand.ExtendedOutputStream), bindingFlags)!;

            PipeStream stdOutStream = (PipeStream)stdOutProp.GetValue(sshCommand)!;
            PipeStream stdErrStream = (PipeStream)stdErrProp.GetValue(sshCommand)!;

            await stdOutStream.DisposeAsync();
            await stdErrStream.DisposeAsync();

            TextWriterPipeStream stdOut = new(Console.Out);
            TextWriterPipeStream stdErr = new(Console.Error);

            stdOutProp.SetValue(sshCommand, stdOut);
            stdErrProp.SetValue(sshCommand, stdErr);

            await sshCommand.ExecuteAsync(cancellationToken);
        }
        catch (Exception e)
        {
            return await Task.FromException<SshCommand>(e);
        }
        finally
        {
            client.Disconnect();
        }
        return sshCommand;
    }

    private sealed class TextWriterPipeStream : PipeStream
    {
        private readonly TextWriter textWriter;

        public TextWriterPipeStream(TextWriter textWriter) : base()
        {
            this.textWriter = textWriter;
        }

        public override void Write(byte[] buffer, int offset, int count)
        {
            base.Write(buffer, offset, count);
            string output = Encoding.UTF8.GetString(buffer, offset, count);
            textWriter.Write(output);
        }
    }
}