如何使用一个 StreamWriter 写入多个底层流？

Question

我正在写文本到 System.IO.StreamWriter。

底层流（在new StreamWriter(underlyingStream)中指定）写入远程文件。（我不认为它的类型是相关的，但为了完整起见，我会提到它是微软 azure CloudBlobStream underlyingStream）。

现在，我想通过在 StreamWriter 和第二个 CloudBlobStream 之间使用 GZipOutputStream compressedUnderlyingStream 来扩展它，同时编写一个具有相同内容的额外压缩文件。

我正在寻找一种方法来将两个 CloudBlobStream 指定为 StreamWriter 的基础流。但我找不到办法。是否存在某种可以组合两个底层流的流类型？或者我怎样才能解决这个问题？请注意，我希望所有内容都保留为流，以最大程度地减少内存中的数据量。

//disregard lack of using statements for this example's sake
CloudBlobStream blobStream = blob.OpenWrite();
CloudBlobStream compressedBlobStream = compressedBlob.OpenWrite();
GZipOutputStream compressorStream = new GZipOutputStream(compressedBlobStream);
//I make the streamwriter here for the regular blob,
///but how could I make the same streamwriter also write to the compressedBlob at the same time?
TextWriter streamWriter = new StreamWriter(blobStream, Encoding.UTF8);

Answer 1

我一时想不出来，但自己写一个也很简单：

class MultiStream : Stream
{
    private List<Stream> streams;

    public Streams(IEnumerable<Stream> streams)
    {
        this.streams = new List<Stream>(streams);
    }

    ...

    public override void Write(byte[] buffer, int offset, int count)
    {
        foreach(Stream stream in streams)
            stream.Write(buffer, offset, count);
    }

    ...
}

如何使用一个 StreamWriter 写入多个底层流？

How to use one StreamWriter to write to multiple underlying streams?

c#

compression

stream

azure

gzipstream