package dap

The 'cancel' request is used by the frontend in two situations:

• to indicate that it is no longer interested in the result produced by a specific request issued earlier
• to cancel a progress sequence. Clients should only call this request if the capability 'supportsCancelRequest' is true. This request has a hint characteristic: a debug adapter can only be expected to make a 'best effort' in honouring this request but there are no guarantees. The 'cancel' request may return an error if it could not cancel an operation but a frontend should refrain from presenting this error to end users. A frontend client should only call this request if the capability 'supportsCancelRequest' is true. The request that got canceled still needs to send a response back. This can either be a normal result ('success' attribute true) or an error response ('success' attribute false and the 'message' set to 'cancelled'). Returning partial results from a cancelled request is possible but please note that a frontend client has no generic way for detecting that a response is partial or not. The progress that got cancelled still needs to send a 'progressEnd' event back. A client should not assume that progress just got cancelled after sending the 'cancel' request.