Hello, Igniters! I want to add the possibility of sending user defined attributes from thin clients. And check them inside custom authenticator during handshake [1].
There is an issue in hardcoded binary writer for JDBC and `IgniteClient`. This writer searches for a classes in the JDK and META-INF/classnames.properties, and tries to sync notdeclared classes with cluster. But fails because current classloading uses discovery. I'd like to keep this writer and allow only primitive types and `String` for user attributes to prevent unexpected fails. I think it is better than changing writer to one with heavy classloading. Is it ok to restrict thin attributes to primitives and 'String'? [1] https://issues.apache.org/jira/browse/IGNITE-12049
