Event callbacks are processed in LIFO order given a backlog of messages

[cursork]

Log of Rs and Ts:

08:27.194 R:  #2: {"Event":{"EventName":"KeyPress","ID":"F1.E","EventID":"b8ae1f33-0fe2-4798-ad71-0fbd950bf842","Info":["f",102,70,0]}} 
08:27.311 R:  #2: {"Event":{"EventName":"KeyPress","ID":"F1.E","EventID":"2d359cc6-289d-4ae1-a896-0fc935903ac9","Info":["l",108,76,0]}} 
08:27.553 R:  #2: {"Event":{"EventName":"KeyPress","ID":"F1.E","EventID":"f93c8db8-7abc-4aff-a161-91897149590b","Info":["i",105,73,0]}} 
08:27.658 R:  #2: {"Event":{"EventName":"KeyPress","ID":"F1.E","EventID":"89c92073-7e7c-44fc-a73d-abdb0533625d","Info":["p",112,80,0]}} 
08:28.228 T:  #2: {"EC":{"EventID":"b8ae1f33-0fe2-4798-ad71-0fbd950bf842","Proceed":1}} 
08:29.252 T:  #2: {"EC":{"EventID":"89c92073-7e7c-44fc-a73d-abdb0533625d","Proceed":1}} 
08:30.279 T:  #2: {"EC":{"EventID":"f93c8db8-7abc-4aff-a161-91897149590b","Proceed":1}} 
08:31.301 T:  #2: {"EC":{"EventID":"2d359cc6-289d-4ae1-a896-0fc935903ac9","Proceed":1}} 

Repro is simply:

'F1'eWC'Form'
'F1.E'eWC'Edit'('Posn' 10 10)('Size' 12 100)('Event' 'KeyPress' 'CBKP')

where CBKP is just a ⎕DL 1 and nothing else.

The messages for the word 'flip' arrive in order (EventIDs starting with) b8, 2d, f9, 89 but Proceeds are issued in the order b8, 89, f9, 2d. While the first one is in its callback waiting on the DL, the others form a backlog.

I believe they must be in the same order? If not, then I believe the client needs to be smarter on this front.

Tested on both main and fix-65-dq.

[cursork]

To clarify what I meant here, I believe the two options are based on whether the client should be able to proactively queue more than one event or not:

• The server must always process events in order per connection.
• The client must always wait for an event response (when required) before the next event is emitted.

It is also possible to do both, as they are not mutually exclusive. However, one negates the necessity of the other, in theory.

[cursork]

eDQ 'F1' works