2.2.18 [W3C-HTML52] Section 4.7.13.5. Loading the media resource

C0031: Buffered data is discarded only if data becomes invalid

The specification states:

 ... Loading the media resource
     ...
     User agents may discard previously buffered data.

EdgeHTML Mode

Buffered data is discarded only if data becomes invalid.

C0030: The preload attribute causes preloading of resources

The specification states:

 ... Loading the media resource
     ...
     The preload attribute is intended to provide a hint to the user agent about what the 
     author thinks will lead to the best user experience. The attribute may be ignored 
     altogether, for example based on explicit user preferences or based on the available 
     connectivity.

EdgeHTML Mode

The preload attribute causes preloading of resources.