Introduce message class resolver

[vjik]

Q	A
Is bugfix?	❌
New feature?	✔️
Breaks BC?	✔️
Tests pass?	✔️
Fix #292

[codecov]

Codecov Report

❌ Patch coverage is 0% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.00%. Comparing base (31c3cb5) to head (266bc9f).

Files with missing lines	Patch %	Lines
src/Message/Serializer/MessageSerializer.php	0.00%	5 Missing ⚠️
...essage/ClassResolver/ArrayMessageClassResolver.php	0.00%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             master    #310   +/-   ##
========================================
  Coverage      0.00%   0.00%           
+ Complexity      336     334    -2     
========================================
  Files            50      51    +1     
  Lines           920     918    -2     
========================================
+ Misses          920     918    -2     

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[samdark]

Suggested change

	'message-class-map' => [],
	'messages' => [],

I'd also move that as 1st array key so it will be message, handlers etc. The drawback here is that we repeat the same thing two times:

'messages' => [
    'process-pdf' => ProcessPdfMessage::class,
],
'handlers' => [
    'process-pdf' => ProcessPdfMessageHandler::class,
],

Could be possibly combined:

'messages' => [
    'process-pdf' => [ProcessPdfMessage::class, ProcessPdfMessageHandler::class],
],

[vjik]

I suggest extracting it into a separate issue.

[samdark]

Thought more about it. Not a good idea since messages are class-only while handlers are definitions.

[samdark]

👍