code: public MultiRuntimeConfigurationBuilder addRuntime(final String runtimeName) {
      Validate.isTrue(SUPPORTED_RUNTIMES.contains(runtimeName), "unsupported runtime " + runtimeName);
  
      this.runtimeNames.add(runtimeName);
      return this;
    }
docs: Adds runtime name to the builder.
  @param runtimeName The name to add
  @return The builder instance