Interface CompletionHandler

Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface CompletionHandler
A callback invoked once when a RequestExecutionEngine run finishes - either because every queued request completed or because the run was cancelled. Register one with RequestExecutionLifetime.onComplete(CompletionHandler) to be notified without blocking a thread.