Decode the MRTR (SEP-2322) requestState as JSON into T, the typed
inverse of the server-side RequestContext.requestStateAs!T (the server
encodes serializeToJson(state).toString()). Returns T.init when the
server sent no state (requestState empty).
Per SEP-2322 requestState is opaque and server-owned: a conformant client
MUST NOT inspect it and normally only echoes it back verbatim on retry. This
accessor is a convenience (e.g. for tests asserting the round-trip shape),
not the expected path. The value is untrusted, so a malformed payload throws.
Decode the MRTR (SEP-2322) requestState as JSON into T, the typed inverse of the server-side RequestContext.requestStateAs!T (the server encodes serializeToJson(state).toString()). Returns T.init when the server sent no state (requestState empty).
Per SEP-2322 requestState is opaque and server-owned: a conformant client MUST NOT inspect it and normally only echoes it back verbatim on retry. This accessor is a convenience (e.g. for tests asserting the round-trip shape), not the expected path. The value is untrusted, so a malformed payload throws.