addDefaults(node) {
    return this.ensureNode(node.id, 'inbound')
      .then((process) => Promise.all(Object.keys(process.component.inPorts.ports).map((key) => {
        // Attach a socket to any defaulted inPorts as long as they aren't already attached.
        const port = process.component.inPorts.ports[key];
        if (!port.hasDefault() || port.isAttached()) {
          return Promise.resolve();
        }
        const socket = internalSocket.createSocket({}, {
          debug: this.debug,
          async: this.asyncDelivery,
        });

        // Subscribe to events from the socket
        this.subscribeSocket(socket);

        return connectPort(socket, process, key, undefined, true)
          .then(() => {
            this.connections.push(socket);
            this.defaults.push(socket);
          });
      })))
      .then(() => {});
  }
@protected
@param {import("fbp-graph/lib/Types").GraphNode} node
@returns {Promise<void>}