Function role_partition 

pub fn role_partition(
    role: &Role,
    partitions: i32,
) -> Result<i32, CoordinationError>

The partition that holds every record of role.

The rule is Kafka’s own key partitioning, which krabka_client_producer::partition_for_key implements: murmur2 of the role name in UTF-8, masked with Utils.toPositive, then the remainder of partitions. krabka-streams-java and krabka-streams-go write the same topic, so they implement the same rule. A change here needs the same change in the two ports.

Both producers of a role call this and pin the partition on the record. The key of a registration and the key of a lease differ, so a partitioner that hashes the key would split one role across two partitions and destroy the total order the succession rules rank on.

Errors

Returns CoordinationError::InvalidConfig when partitions is not positive.