[PROTON-2195] Tidy up/Finalise the API around proactor event batches

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: proton-c-0.30.0
• Fix Version/s: proton-c-0.31.0
• Component/s: proton-c
• Assignee: Andrew Stitcher
• Reporter: Andrew Stitcher
• Created: 23/Apr/20 01:24
• Updated: 14/May/20 09:30
• Resolved: 23/Apr/20 02:00

Description

There are a number of issues with the pn_event_batch_t type in proton:

• The pn_event_batch_t type should be a type whose details are private and only meaningful to the proactor because it is only the proactor API batches events for serialisation. However it is defined in the event.h header file and its only operation pn_event_batch_next() is actually in the proton core library.
• The type is used internally in the connection_driver API which is in the proton core library. This use is unnecessary as the batches are never even exposed by the connection_driver API. Indeed it's hard to see what use the connection_driver could make of an event batch since it only knows about events from the proton core library which only returns events and never batches.

The proactor and connection_driver APIs which are the ones affected are both marked as Unsettled APIs so these changes are currently acceptable.