code: public JsonObject putNullAndEncrypt(String name, String providerName) {
          addValueEncryptionInfo(name, providerName, true);
          content.put(name, null);
          return this;
      }
docs: Store a null value as encrypted identified by the field's name.
  
  This method is equivalent to calling {@link #put(String, Object)} with either
  {@link JsonValue#NULL JsonValue.NULL} or a null value explicitly cast to Object.
  
  Note: Use of the Field Level Encryption functionality provided in the
  com.couchbase.client.encryption namespace provided by Couchbase is
  subject to the Couchbase Inc. Enterprise Subscription License Agreement
  at https://www.couchbase.com/ESLA-11132015.
  
  @param name The null field's name.
  @param providerName Crypto provider name for encryption.
  @return the {@link JsonObject}