For better API design, I'd put FarcasterAPIRequest::payload here, but let's keep it as is for now for simplicity

This can be replaced with http_client.{get,put}().bearer_auth(farcaster_dc_token) but can stay this way too.

Its internal implementation is exactly the same, the only exception is that it uses header_sensitive() which makes this header redacted when printing using Debug trait.

To do it here, you would have to do it like this:

let bearer = format!("Bearer {}", farcaster_dc_token);
let mut bearer_header = HeaderValue::from_str(&bearer)?;
bearer_header.set_sensitive(true);
headers.insert(AUTHORIZATION,  bearer_header);

Some common parts could be extracted above the enum match branching

let request_builder = self.http_client.request(method, url).headers(headers);

but it's not worth in the current design without applying my suggestions about the APIMethod enum