@startuml
scale max 900*520
skinparam backgroundColor transparent
skinparam shadowing false
skinparam defaultFontName "DejaVu Sans Mono"
skinparam defaultFontSize 13
skinparam rectangleBorderColor #2b6f8e
skinparam rectangleBackgroundColor #edf6fa
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top to bottom direction
title A8 PATTERNS — choose queue payload ownership explicitly

rectangle "01 VALUE MESSAGE\nQueueMessage bytes copied\nproducer may reuse source" as Value
rectangle "02 POINTER MESSAGE\naddress copied only\nlifetime remains external" as Pointer
rectangle "03 OWNERSHIP CONTRACT\nwho allocates? who frees?\ncan producer mutate?" as Contract
rectangle "04 FC05 DECISION\nsmall trivially copied value\nchecksum proves integrity" as Decision

Value --> Contract
Pointer --> Contract
Contract --> Decision
@enduml