@CanIgnoreReturnValue
    public Builder withoutExpiration() {
      this.withoutExpiration = true;
      return this;
    }
Allow generating tokens without an expiration.

<p>For most applications of JWT, an expiration date should be set. This function makes sure
that this is not forgotten, by requiring to user to explicitly state that no expiration
should be set.
java_src/src/main/java/com/google/crypto/tink/jwt/RawJwt.java