code: @Override
      public FileIO setAppend(final boolean... append) {
          this.append = (append != null) && ((append.length == 0) || ((append.length > 0) && append[0]));
          return this;
      }
docs: Set whether output should be append to existing file. When this method is not invoked, or
  invoked with 'false', The file will be replaced on writing operations.
  
  @param append
  optional parameter, default is true.
  @return this to provide a fluent API.