Constant MAX_THREADS_PER_REPLICA 

pub const MAX_THREADS_PER_REPLICA: usize = 256;

The maximum number of threads that can be registered with a replica. If more than this number of threads try to register, the register() function will return None.

Important

If this number is adjusted due to the use of the arr_macro::arr macro we have to adjust the 256 literals in the new constructor of Replica.