This diff increases the performance of media encryption/decryption by using newly introduced methods instead
of basing on response.arrayBuffer() which uses slow base64 under the hood. Details are described in parent diffs and
in the task issue.
Depends on D7974
This type could be skipped since it's obvious this will be the same as the return type of the entire selector but I saw in codebase versions with/without type in last callback so deffering to you