A FileCopy is a handle to an internal data structure describing a file copy operation in the File built-in functions. The file copy operations allow for speedy copying of a file by copying it in block sections. File data and details of the operation are optimized and hidden from the caller, making writing the required code simpler and easier than copying the file with the other, more basic File built-in functions. File.CopyStart() is used to create a copy, then other operations may be used to query information about the copy procedure or continue copying the file in blocks until done.