ITextBuffer buffer = GetBuffer(); int start = 5; int length = 10; int numDeleted = buffer.Delete(start, length);In this example, we get an ITextBuffer object from some source (not shown). We then call Delete on the buffer, specifying start as the start index of the range to be deleted, and length as the number of characters to be deleted. The method returns the actual number of characters deleted, which we store in numDeleted for later use. Package library would depend on the specific implementation of ITextBuffer. It is most likely part of a larger text editing or document processing library, such as Microsoft's Visual Studio SDK or Roslyn code analysis library.