* fix several tests that were using akka.remote.netty.tcp config
* replace akka.tcp with akka in more places
* some doc cross references to remoting.md
* ⇒, →, ←
* because we don't want to show them in documentation snippets and
then it's complicated to avoid that when snippets are
located in src/test/scala in individual modules
* dont replace object `→` in FSM.scala and PersistentFSM.scala
* Add CopyrightHeader support for sbt-boilerplate plugin.
* Add CopyrightHeader support for `*.proto` files.
* Add regex match for both `–` and `-` for CopyrightHeader.
* Add CopyrightHeader support for sbt build files.
* Update copyright from 2018 to 2019.
* keep track of delta interval versions and skip deltas
that are not consequtive, i.e. when some delta message was lost
* send the delta versions in the full state gossip to sync up the
expected versions after dropped deltas
* implementation of deltas for ORSet
* refactoring of the delta types to allow for different type for the
delta and the full state
* extensive tests
* mima filter
* performance optimizations
* simple pruning of deltas
* Java API
* update documentation
* KeyId type alias
* Use InternalApi annotation
* delta GCounter and PNCounter
* first stab at delta propagation protocol
* send delta in the direct write
* possibility to turn off delta propagation
* tests
* protobuf serializer for DeltaPropagation
* documentation
* fix merge issues of DataEnvelope and its pruning
* simplify by removing the tombstones, which didn't work in all cases anyway
* keep the PruningPerformed markers in the DataEnvelope until configured
TTL has elapsed (wall clock)
* simplify PruningState structure
* also store the pruning markers in durable data
* collect removed nodes from the data, listing on MemberRemoved is not enough
* possibility to disable pruning altogether
* documented caveat for durable data
Previously know as [patriknw/akka-data-replication](https://github.com/patriknw/akka-data-replication),
which was originally inspired by [jboner/akka-crdt](https://github.com/jboner/akka-crdt).
The functionality is very similar to akka-data-replication 0.11.
Here is a list of the most important changes:
* The package name changed to `akka.cluster.ddata`
* The extension was renamed to `DistributedData`
* The keys changed from strings to classes with unique identifiers and type information of the data values,
e.g. `ORSetKey[Int]("set2")`
* The optional read consistency parameter was removed from the `Update` message. If you need to read from
other replicas before performing the update you have to first send a `Get` message and then continue with
the ``Update`` when the ``GetSuccess`` is received.
* `BigInt` is used in `GCounter` and `PNCounter` instead of `Long`
* Improvements of java api
* Better documentation
