pub fn new(
        access_key: String,
        secret_access_key: String,
        token: Option<String>,
        valid_for: Option<i64>,
    ) -> StaticProvider {
        StaticProvider {
            credentials: AwsCredentials::new(access_key, secret_access_key, token, None),
            valid_for,
        }
    }
Creates a new Static Provider. This should be used when you want to statically, or programmatically
provide access to AWS.

`valid_for` is the number of seconds for which issued tokens are valid.
rusoto/credential/src/static_provider.rs