CRDTDictionary

Swift CRDT Dictionary implementation.

Summary

Implementation of a CRDT Dictionary that allows conflict-free replication accross different systems by merging itself with other replicas.

Data validity is based on a Timestamp, last added element wins. Last-Write-Wins.

Assumes there can't exist different values with same key in the dictionary. Adding a new value for an existing key will act as an update. If key-value pairs were needed to be unique combinations we would need to modify the dictionary to accept multiple CRDTElement per key and then filter out to get the one with the latest timestamp.
Timestamp should be unique. Adding a new key-value for an existing key with the same timestamp will win over existing key-value.
Generic type needs to be specified when initializing the CRDTDictionary, if we wanted the dictionary to have different concrete types we could do at function level and let the caller infer the type.
CRDTElement is exposed when retrieving elements from the dictionary but could be changed to key-value tuples.
Added GMT Date extension as to unify timezones and prevent conflicting timezones when merging dictionaries from different devices.