NewBlockRepository returns a new instance of the BlockRepository with the specified Redis client and expiration time.

NewSubscriberRepository creates a new instance of SubscriberRepository redis - an instance of redis.Client for communication with the Redis database expirationTime - the expiration time for subscribers stored in the Redis database.

BlockRepository is a structure that holds information about the current block.

SubscriberRepository is a structure to store subscribers in a Redis database.