public static ServiceRequestContext get(GraphQLContext graphQLContext) {
        requireNonNull(graphQLContext, "graphQLContext");
        final ServiceRequestContext ctx = graphQLContext.get(GRAPHQL_CONTEXT_KEY);
        if (ctx == null) {
            throw new IllegalStateException("missing request context");
        }
        return ctx;
    }
Retrieves the current {@link ServiceRequestContext} from the specified {@link GraphQLContext}.
For example:
<pre>{@code
new DataFetcher<>() {
    @Override
    public String get(DataFetchingEnvironment env) throws Exception {
        final GraphQLContext graphQLContext = env.getGraphQlContext();
        final ServiceRequestContext ctx = GraphqlServiceContexts.get(graphQLContext);
        // ...
    }
};
}</pre>

@throws IllegalStateException if the specified {@link GraphQLContext} doesn't contain
                              a {@link ServiceRequestContext}.
graphql/src/main/java/com/linecorp/armeria/server/graphql/GraphqlServiceContexts.java