This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
public interface PushbackPolicy<T,U extends java.util.concurrent.BlockingQueue<PushEvent<? extends T>>>
A PushbackPolicy is used to calculate how much back pressure to apply
based on the current buffer. The PushbackPolicy will be called after
an event has been queued, and the returned value will be used as back