Warning: Can't perform a React state update on an unmounted component

Bom dia, estou recebendo o warningao me inscrever com subscribe.

Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in the componentWillUnmount method.

Qual a razão dele e como resolve-lo?

Código:

export default class Usuarios extends Component {

    constructor(props) {
        super(props);
        this.state = {usuarios : []}
    }

    componentWillMount() {
        this.props.store.subscribe(() => {
            this.setState({usuarios: this.props.store.getState()});
        })
    }
    componentDidMount() {
        UsuarioApi.listar(this.props.store)
    }
...
}