Perf: concrete mqbi::DispatcherEvent events

[678098]

Changes

• Add new package group mqbevt.
• Make mqbi::DispatcherEvent a base class for 12 concrete dispatcher event types. Move the sources of concrete event types to mqbevt package group.
• Keep only the required minimum field set for each concrete dispatcher event type.
• Include concrete event types in .cpp files, keep forward declarations to them in .h. This prevents leaking of heavy includes such as bmqp_protocol.h.
• Make event type a static property of each dispatcher event implementation.
• Get rid of isRelay where it's not needed.
• Replace named concrete event accessors like asCallbackEvent() with templated ones like the<mqbevt::CallbackEvent>().
• Manage separate shared object pools for different event types.

Benchmarks

Linux x86_64

Before:

Name                  | sizeof | constructor, ns/op
---------------------------------------------------
mqbi::DispatcherEvent |    768 |            46.6131               

After:

                       Name | sizeof | constructor, ns/op | reset (ns/op)
=========================================================================
           mqbevt::AckEvent |     96 |           6.145480 |      3.668200
      mqbevt::CallbackEvent |     64 |           6.136220 |      2.279000
  mqbevt::ClusterStateEvent |     48 |           5.440250 |      2.329530
       mqbevt::ConfirmEvent |     72 |           6.136910 |      3.357720
mqbevt::ControlMessageEvent |    208 |           9.437210 |      4.473490
    mqbevt::DispatcherEvent |    104 |           8.259750 |      2.133980
          mqbevt::PushEvent |    256 |          17.632800 |      5.508160
           mqbevt::PutEvent |    136 |           6.687370 |     12.936720
       mqbevt::ReceiptEvent |     48 |           5.165990 |      1.826960
      mqbevt::RecoveryEvent |     48 |           5.702260 |      2.432480
        mqbevt::RejectEvent |     80 |           5.820400 |      3.038740
       mqbevt::StorageEvent |     48 |           6.152550 |      2.431490

Mac M2

Before:

Name                  | sizeof | constructor, ns/op 
---------------------------------------------------
mqbi::DispatcherEvent |    768 |             197.51 

After:

                       Name | sizeof | constructor, ns/op | reset (ns/op)
=========================================================================
           mqbevt::AckEvent |     96 |          19.357500 |      9.600840
      mqbevt::CallbackEvent |     64 |          25.825420 |      5.437500
  mqbevt::ClusterStateEvent |     48 |          12.276250 |      5.537080
       mqbevt::ConfirmEvent |     72 |          13.469590 |      7.685420
mqbevt::ControlMessageEvent |    208 |          35.178330 |     17.594170
    mqbevt::DispatcherEvent |    104 |          34.957500 |      7.789590
          mqbevt::PushEvent |    256 |          65.809580 |     26.294170
           mqbevt::PutEvent |    136 |          52.033750 |     47.957500
       mqbevt::ReceiptEvent |     48 |           9.312500 |      4.004170
      mqbevt::RecoveryEvent |     48 |           8.900420 |      4.003750
        mqbevt::RejectEvent |     80 |          10.410410 |      5.669160
       mqbevt::StorageEvent |     48 |           8.735410 |      4.276250

[678098]

I have simplified isRelay usage. For some event types, it is always true or always false. In such cases, possible to remove this flag fully.
Also I have removed other unused fields. In this case, we don't access compression algorithm type for PUT events, so there is no need to set it or keep it.
With concrete event types, it is easier to keep track on what is used and what is not used.

[678098]

Only the mqbs::FileStore has dispatchEvent and execute.
These functions might be defined for mqbi::DispatcherClient and be used more often by its implementations. It can be done in the next refactor, here I decided not to add this to the diff.

[678098]

I did not try to optimize memory layouts in this PR for simplicity, will do it later. We can win a few more bytes in some cases.

[678098]

Self-review is ok

[678098]

@hallfox applied fixes in the second commit

[hallfox]

Since this compiles to nothing on Solaris it's still good to have the const qualifier here. According to the BDE docs this is a recommended way for using the CONSTEXPR keyword.

[678098]

Fixed