public OAuth1aToken build() {
        checkState(consumerKey != null, "consumerKey is not set.");
        checkState(token != null, "token is not set.");
        checkState(signatureMethod != null, "signatureMethod is not set.");
        checkState(signature != null, "signature is not set.");
        checkState(timestamp != null, "timestamp is not set.");
        checkState(nonce != null, "nonce is not set.");
        return new OAuth1aToken(consumerKey, token, signatureMethod, signature, timestamp, nonce,
                                version, additionalsBuilder.build(), realm);
    }
Returns a newly-created {@link OAuth1aToken} based on the properties set so far.
core/src/main/java/com/linecorp/armeria/common/auth/OAuth1aTokenBuilder.java