This is a part of the blog post series that explain the new streaming API for Sitefinity 3.7 SP3. You can view the TOC in the first blog post.
I talked about the API of streaming, explained why it was needed and some of its limitations. Now, I will give more information about limitations.
First, let me define what I mean by corner case, or an exception. Although we tried not to load the whole binary data in memory, there are some places where it is impossible to do so. These rare cases, when the whole binary data is needed, I call corner cases.
Case 1: Uploading images
When in the Images & Documents module, some information is needed that requires the whole binary data. For example, the image header is checked to ensure that the image type is appropriate (of the allowed types - jpeg, png, etc.).
Case 2: Creating image thumbnails (or resizing them)
To resize an image, we need the whole binary data in memory. This applies to uploading images and downloading resized images - like thumbnails or by specifying width and height query string parameters.
Case 3: Creating video thumbnails
While the thumbnail generation is done in DexterLib via streams, a thumbnail image still needs to be saved. Saving thumbnails works in with byte[].
Case 4: MetaWebblog API
Data is sent & received by finite data structures. In other words, we receive a byte[]. Streaming will work as expected, but will load the whole media object in memory and the wrap it further in MemoryStream.
Conclusion
By showing you these corner cases is I have completed the blog post series about the new Streaming API in Sitefinity 3.7 SP3. I believe they will let you make informed decisions when writing your own streaming provider.