What is [Symbol(kHeaders)] and how do I parse it as headers

I am having trouble parsing the header retrieved from graphql’s context, what I would like to do is to basically forward the headers from the request into the response

My gateway:

GraphQLModule.forRootAsync<ApolloGatewayDriverConfig>({
    driver: ApolloGatewayDriver,
    inject: [ConfigService],
    useFactory: async(configService: ConfigService) => ({
        server: {
            introspection: true,
            playground: true,
            cache: 'bounded'
        },
        gateway: {
            buildService: (url) => new CustomDataSource(url),
            supergraphSdl: ...
        }
    })
})

My CustomDataSource which should forward headers:

export class CustomDataSource  extends RemoteGraphQLDataSource {
    constructor(config: any) {
        super(config);
        this.fetcher = fetcher.defaults({
            maxSockets: Infinity,
            strictSSL: false,
            retry: false,
        })
    }

    willSendRequest({context, request }) {
        console.log('context', context.req); // <---- here
        request.http?.headers.set('authorization', context.req.authorization);
    }
}

My issue now is that the context.req.headers do not exist when it should and logging it out gives me headers in a different name as kHeaders instead which I am unsure of how to parse this.

context.req:

{
  ...,
  ...,
  [Symbol(kHeaders)]: {
    authorization: 'abcdefg'
  }
}

I tried something like context.req[‘Symbol(kHeaders)’] which returns me cannot read properties, would like to know why is my headers returned this way and how do I parse this