# Package io.vertx.rxjava3.core

- Class Summary
  Class | Description
  --- | ---
  AbstractVerticle |
  Context | The execution context of a `Handler` execution.
  ExpectationTransformer<T,​U> |
  FlowableHelper |
  MaybeHelper |
  ObservableHelper |
  Promise<T> | Represents the writable side of an action that may, or may not, have occurred yet.
  RxHelper |
  SingleHelper |
  Timer | A timer task that can be used as a future.
  Vertx | The entry point into the Vert.x Core API.
  VertxBuilder | A builder for creating Vert.x instances, allowing to configure Vert.x plugins: metrics tracing cluster manager Example usage:
  WorkerExecutor | An executor for executing blocking code in Vert.x .