@CanIgnoreReturnValue
    public Builder addJsonObjectClaim(String name, String encodedJsonObject)
        throws JwtInvalidException {
      JwtNames.validate(name);
      payload.add(name, JsonUtil.parseJson(encodedJsonObject));
      return this;
    }
Adds a custom claim encoded in a JSON {@code String} to the JWT.
java_src/src/main/java/com/google/crypto/tink/jwt/RawJwt.java