Provides a file reading interface for reading all or parts of files located on a remote FTP server, including emulation of seek and support for downloading only the parts of the file requested.
Support for skipping the beginning of the file is implemented with the FTP REST command, which starts a retrieval at any point in the file. Support for skipping the end of the file is implemented with the FTP ABOR command, which stops the transfer. With these two commands and some careful tracking of the current file position, we're able to reliably emulate a seek/read pair, and get only the parts of the file that are actually read.