List all handlers attached to the Evt. Returns an array of Handler<T,any>.
Here a use case detaching all handlers that uses a given matcher:
import { Evt } from"evt";constevtShape=newEvt<Shape>();evtShape.attach( matchCircle, circle =>console.log("1:", circle));evtShape.attachOnce( matchCircle, circle =>console.log("2:", circle));evtShape.waitFor(matchCircle).then(circle =>console.log("3:", circle)) ;//Only handler that does not use matchCircle as operator.evtShape.attach(circle =>console.log("4:", circle))evtShape.getHandlers().filter(({ op }) => op === matchCircle).forEach(({ detach }) =>detach()) ;//Prints only "4: ..." other handlers are detached.evtShape.post({ "type":"CIRCLE","radius":300 });