Bitmask representing no types of cancellation.

Requests cancellation where, following a successful cancellation, the only safe operations on the I/O object are closure or destruction.

Requests cancellation where a successful cancellation may result in partial side effects or no side effects. Following cancellation, the I/O object is in a well-known state, and may be used for further operations.

Requests cancellation where a successful cancellation results in no apparent side effects. Following cancellation, the I/O object is in the same observable state as it was prior to the operation.

Bitmask representing all types of cancellation.