How to convert a Guava ListeanbelFuture to Cats Async

GuavaFutures.scala

import cats.effect.Async
import com.google.common.util.concurrent.{FutureCallback, Futures, ListenableFuture}

import scala.concurrent.ExecutionContext

object GuavaFutures {

  implicit class RichListenableFuture[T](lf: ListenableFuture[T]) {

    def toAsync[F[_]: Async](implicit ec: ExecutionContext): F[T] = {
      Async[F].async { cb =>
        Futures.addCallback(lf, new FutureCallback[T] {
          override def onFailure(t: Throwable): Unit = cb(Left(t))
          override def onSuccess(result: T): Unit = cb(Right(result))
        }, (command: Runnable) => ec.execute(command))
      }
    }
  }
}