import "context"
// create a client (safe to share across requests)
client := graphql.NewClient("https://machinebox.io/graphql")
// make a request
req := graphql.NewRequest(`
    query ($key: String!) {
        items (id:$key) {
            field1
            field2
            field3
        }
    }
`)
// set any variables
req.Var("key", "value")
// set header fields
req.Header.Set("Cache-Control", "no-cache")
// define a Context for the request
ctx := context.Background()
// run it and capture the response
var respData ResponseStruct
if err := client.Run(ctx, req, &respData); err != nil {
    log.Fatal(err)
}