In your custom task, the Secure FTP Task, you implemented your custom logic in the Validate() and Execute() methods. You exposed the settings needed to perform the file transfer operations as public members of the SecureFTP class.
The Microsoft.SqlServer.Dts.Runtime.Task base class allows the task to be used in an SSIS control flow, its public properties are accessible from SSDT, and the custom programmatic logic allows the task to be validated and executed.
If configured correctly, the task can either download files from, or upload them to, an FTP site.
When you used the task in the SecureFtpTask.dtsx SSIS package, you were not able to configure it using a custom editor, because this recipe did not cover the design of such ...