Sets the value of a field which can accept a string as a value. This is called on each keystroke when a user types into an edit field

SetUsageScenario is the provider's cue that it's going to be asked for tiles in a subsequent call.

This function will be called by LogonUI after SetUsageScenario succeeds. Sets the User Array with the list of users to be enumerated on the logon scre

LogonUI calls this to tell us to release the callback.

Called by LogonUI when the ICredentialProviderEvents callback is no longer valid.