public void WriteTextTo(TextWriter writer, int offset, int length)
 {
     if (writer == null)
     {
         throw new ArgumentNullException(nameof(writer));
     }
     ReadOnlyTextDocument.WriteTextTo(writer, offset, length);
 }
 public void WriteTextTo(TextWriter writer)
 {
     if (writer == null)
     {
         throw new ArgumentNullException(nameof(writer));
     }
     ReadOnlyTextDocument.WriteTextTo(writer);
 }