(This is in response to this conversation on Twitter.)
I don't recommend using dynamic or reflection to call platform-specific APIs in most cases. Generally, create an abstraction and then implement it in a platform-specific API. The nice thing about our portable HttpClient package is that we do that for you so you pretty much don't have to worry about it.
WriteStreamBuffering can be disabled on WP8 (but not WP7). When using the latest RC of portable HttpClient 2.2 on WP8, we will disable it automatically for you under certain conditions. I believe those conditions are that you've disabled automatic redirection and authentication. @theesj can confirm that.
Here are some blog posts about calling platform-specific APIs from PCLs:
- Using Target-Specific Code in a Portable Library
- [How to Make Portable Class Libraries W