@Input
  @Optional
  public String getContainerizingMode() {
    String property = System.getProperty(PropertyNames.CONTAINERIZING_MODE);
    return property != null ? property : containerizingMode.get();
  }
Should be called using {@link org.gradle.api.plugins.ExtensionContainer#create}.

@param project the injected gradle project
jib-gradle-plugin/src/main/java/com/google/cloud/tools/jib/gradle/JibExtension.java