code: public static ClassInjector of(File folder, Target target, Instrumentation instrumentation) {
              return new UsingInstrumentation(folder, target, instrumentation, new RandomString());
          }
docs: Creates an instrumentation-based class injector.
  
  @param folder          The folder to be used for storing jar files.
  @param target          A representation of the target path to which classes are to be appended.
  @param instrumentation The instrumentation to use for appending to the class path or the boot path.
  @return An appropriate class injector that applies instrumentation.