Function sign_request_at 

pub fn sign_request_at<S: Signer>(
    request: &CanonicalRequest<'_>,
    integrity_token: &str,
    created: i64,
    nonce: &str,
    signer: &S,
) -> Result<SignedHeaders, SignError<S::Error>>

Signs request with an explicit created and nonce, for deterministic output in tests and test vectors. Production callers should use sign_request.

Errors

Returns a SignError when the parameters are invalid or the signer fails.