Parse the exact request union into a new request object, including bounded,
canonical XDR. Unknown methods fail with 4200; malformed known requests fail
with -32602. This validates input, not origin permission or prior approval.
Bridges must bound raw messages before JSON parsing: at most 2,096,922 unsigned
or 2,097,154 signed transaction-hex characters, including 0x.
Parse the exact request union into a new request object, including bounded, canonical XDR. Unknown methods fail with 4200; malformed known requests fail with -32602. This validates input, not origin permission or prior approval. Bridges must bound raw messages before JSON parsing: at most 2,096,922 unsigned or 2,097,154 signed transaction-hex characters, including 0x.