Existing C-API tests could further verify sample_info.extra_data #273
Description
#272 adds some test coverage for this in the AV1 case -- we explicitly verify the binary blob exposed via the API is what we expect. There's a little coverage for this in the test_fragment.rs tests too, but they only check the length, rather than the actual data.
We could add some checks to existing tests to make sure the extra data takes on the value we expect. This should be relatively straight forward (particularly if #272 merges and provides prior art).