public TBase<?, ?> result() {
        if (isException()) {
            throw new IllegalStateException("not a reply but an exception");
        }
        assert result != null;
        return result;
    }
Returns the result of this reply.

@throws IllegalStateException if the type of this reply is not {@link TMessageType#REPLY}
thrift/thrift0.13/src/main/java/com/linecorp/armeria/common/thrift/ThriftReply.java