got := 0
				for b := range in {
					PutByteBuffer(b)
					got++
				}
				if got != requests {
					return NewRemoteErrf("wrong number of requests. want %d, got %d", requests, got)
				}
				return nil
			},

			Subroute:    "some-subroute",
			OutCapacity: 1,
			InCapacity:  1, // Only one message buffered.
		}))

// The error type is not preserved.
func NewRemoteErr(err error) *RemoteErr {
	if err == nil {
		return nil
	}
	r := RemoteErr(err.Error())
	return &r
}

// NewRemoteErrf creates a new remote error from a format string.
func NewRemoteErrf(format string, a ...any) *RemoteErr {
	r := RemoteErr(fmt.Sprintf(format, a...))
	return &r
}

// NewNPErr is a helper to no payload and optional remote error.