OptionaldefaultRail to use when a request omits one; defaults to the first configured rail.
OptionaldigestHex SHA-256 of the payload bytes; defaults to Web Crypto.
OptionalfetchFetch implementation; defaults to the global fetch.
Optionalinit: RequestInitOptionalnowUnix seconds clock for event timestamps; defaults to Date.now()/1000.
Configured rails + their servers.
Signs NIP-98 / Blossom auth events. Required.
Options for createHttpUploader.