val apolloClient = ApolloClient.Builder() .addHttpHeader("conference", “Android Makers”) .build() apolloClient.query(myQuery) .addHttpHeader("conference", "Devfest Lille") .httpHeaders(emptyList()) .execute() fun <D: Query.Data> ApolloClient.myQuery(query: Query<D>): ApolloCall<D> { return query(query).addHttpHeader("conference", "Devfest Lille") }