public void put(NameValuePair pair) {
    throwIfImmutable();

    if (pair == null) {
      throw new NullPointerException("pair == null");
    }

    elements.put(pair.getName(), pair);
  }
Put an element into the set of (name, value) pairs for this instance. If there is a preexisting
element with the same name, it will be replaced by this method.

@param pair {@code non-null;} the (name, value) pair to place into this instance
android/android_framework/dex-maker/src/main/java/com/android/dx/rop/annotation/Annotation.java