SSSSCryptoCallbacks.getSecretStorageKey may return Promise<void>
SSSSCryptoCallbacks.getSecretStorageKey may return Promise<void>

If no result is found, the function may reach the last line without `return` ever being called.
matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk