Return Promise from start()

src/index.js

@@ -10,6 +10,7 @@ class Vain extends Emitter {
 	}
 
 	start() {
+		return new Promise(resolve => {
 			const startTime = Date.now();
 
 			let found;
@@ -44,11 +45,15 @@ class Vain extends Emitter {
 			const duration = endTime - startTime;
 			const addressesPerSecond = Math.floor(attempts / (duration / ONE_SECOND));
 
-		this.emit('found', {
+
+			const result = {
 				duration,
 				addressesPerSecond,
 				address,
 				wif: keyPair.toWIF()
+			};
+			this.emit('found', result);
+			resolve(result);
 		});
 	}
 }