error: Cannot specify both 'json' and 'body' options.

       Use 'json' for JSON data (automatically sets Content-Type: application/json):
       fetch!(POST url, json: {{ "key": "value" }})

       Use 'body' for raw bytes:
       fetch!(POST url, body: raw_bytes)
 --> tests/ui/fetch/json_and_body_conflict.rs:6:16
  |
6 |       let _req = fetch!(POST "https://example.com",
  |  ________________^
7 | |         json: { "key": "value" },
8 | |         body: data
9 | |     );
  | |_____^
  |
  = note: this error originates in the macro `fetch` (in Nightly builds, run with -Z macro-backtrace for more info)
