The HTTP request message body as stream. POST data should be here. If a
stream is set, which overrides the message body, the stream must have
all the content data available by the time the WebResourceRequested
event deferral of this response is completed. Stream should be agile or
be created from a background STA to prevent performance impact to the UI
thread. Null means no content data. IStream semantics apply
(return S_OK to Read runs until all data is exhausted).
The HTTP request message body as stream. POST data should be here. If a stream is set, which overrides the message body, the stream must have all the content data available by the time the WebResourceRequested event deferral of this response is completed. Stream should be agile or be created from a background STA to prevent performance impact to the UI thread. Null means no content data. IStream semantics apply (return S_OK to Read runs until all data is exhausted).