modules/jooby-gson/src/main/java/org/jooby/json/Gzon.java
public Gzon doWith(final Consumer<GsonBuilder> configurer) {
    requireNonNull(configurer, "Configurer callback is required.");
    this.configurer = (gson, conf) -> configurer.accept(gson);
    return this;
  }
public Gzon doWith(final Consumer<GsonBuilder> configurer) {
    requireNonNull(configurer, "Configurer callback is required.");
    this.configurer = (gson, conf) -> configurer.accept(gson);
    return this;
  }
Configurer callback.

<pre>
{
use(new Gzon().doWith((builder, config) {@literal ->} {
builder.setPrettyPrint();
// ...
});
}
</pre>

@param configurer A callback.
@return This instance.