Question: GetStream copy existing buffer use case

[osexpert]

docs says:

You can also provide an existing buffer. It’s important to note that the data from this buffer will be copied into a buffer owned by the pool:

var stream = manager.GetStream("Program.Main", sourceBuffer, 
                                    0, sourceBuffer.Length);

But if using MemoryStream, no copy will be done?

var stream = new MemoryStream(sourceBuffer);

So who want to copy (and double the amount if memory used) vs. just wrap it, like MemoryStream does?

I made this mistake myself, before I read the docs I just changed all use of MemoryStream to RecyclableMemoryStream, but then I read that GetStream(byte[]) copies and changed all cases where MemoryStream was used for reading, back to MemoryStream.

I think this feature is weird (GetStream copy existing data) and could make more harm (people using as drop in replacement without reading\understanding the docs and GetStream(byte[]) increase memory use) than good? Or maybe it has a good use case, maybe an example would be nice.

Thanks.

[benmwatson]

I would never recommend using this library without reading the documentation. There are lots of gotchas every time you take memory management on yourself, and this is a good example.

For cases where you just want to wrap an existing buffer in a stream, the existing MemoryStream is good.