anchor.diff:  
   Your commands and events are serialized to `JSON` and stored into `Postgres`
   
  -** Using your own https://github.com/crabzilla/crabzilla/blob/main/crabzilla-command/src/main/java/io/github/crabzilla/JsonObjectSerDer.kt[JsonObjectSerDer] implementation.
  +** Using your own https://github.com/crabzilla/crabzilla/blob/main/crabzilla-stack/src/main/java/io/github/crabzilla/JsonObjectSerDer.kt[JsonObjectSerDer] implementation.
   ** Using `crabzilla-json-kotlinx` implementation based on https://kotlinlang.org/docs/serialization.html[Kotlin serialization] .
   ** Using `crabzilla-json-jackson`  implementation based on https://github.com/FasterXML/jackson-module-kotlin[Jackson Kotlin Module].
   
  
positive.code: ** what events to subscribe, filtering by state type (aggregate root) or event type.
  ** a very simple interval policy resulting in an exponential backoff behavior. Crabzilla applies a jitter from 0 up to 1 second.
  ** a sink:
  *** to an implementation of https://github.com/crabzilla/crabzilla/blob/main/crabzilla-command/src/main/java/io/github/crabzilla/EventProjector.kt[EventProjector] implementation in order to update your view model in Postgres.
  *** to Vertx EventBus. You must handle idempotency.
  **** using request reply (at least once).
  **** using blocking request reply (at least once).
  
negative.code: 
  == Approach
  
  * It uses https://vertx.io/docs/vertx-pg-client/java/[Vertx] `non-blocking IO` Postgres driver.
  * It uses key `Postgres` features: json, notification and advisory locks.
  * It tries to use idiomatic Kotlin: type safeness: immutability, pattern matching, honouring your constructors.
  
  == crabzilla-core
  
  To express your domain model.
  
  * State transitions occurs after computing results of pure functions `(State, Event) -> State`.
  * Tests in BDD way without any dependency to Vertx: only to `crabzilla-core`:
  ** given command, then assertion
  ** given events, when command, then assertion
  ** given commands or events in any order, then assertion
  
  == crabzilla-stack
  
  === Command
  
  