Message delivery report callback - dr_msg_cb in librdkafka

In the below documentation link of librdkafka it is told that implementing dr_msg_cb callback is optional.

https://github.com/confluentinc/librdkafka/blob/master/INTRODUCTION.md#message-reliability:~:text=The%20delivery%20report%20callback%20is%20optional%20but%20highly%20recommended.

Im running an application where performance is most considered so I don't want to poll for delivery status for each and every message.

Q1)What are the consequences if I don't implement dr_msg_cb?

Q2)One problem I heard without dr_msg_cb callback is application can silently drop messages after max_retries.Can I set my producer to idempotent and max_retries=INT_MAX to solve this issue?