OptionalattemptFrequency of onAttempt calls (default every 1 attempt).
OptionalmaxMax nonces to try before giving up. Default 1_000_000.
OptionalnonceOverride the starting nonce (default: challenge.header_context.nonce64_start).
OptionalonOptional callback fired every N attempts for progress reporting.
Options for the pure-JS solver (
Solver.solvewithmode: 'pure-js').