B2 file name that was checked.
Locally-computed SHA-1, or null if no local file was provided.
Human-readable failure reason; undefined on success.
Remote SHA-1 result: normalized lowercase digest when comparable, raw B2
value for non-comparable headers such as none or unverified:<sha1>,
or null when B2 does not expose one.
Server-reported byte size of the remote object.
True when remote SHA-1 matches the expected value.
Result of verifyCommand.