Note when a shared field needs option instead of voption - #20594
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The voption guidance said no field is ever a reason to pick option, including ones shared between threads. That is wrong for a lock-free field: option is always one atomic-sized reference, voption is a struct that can span more than one word and tear on an unsynchronized write. PR dotnet#20523 hit this for a Position field a text-view listener writes and the project options reactor reads. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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The voption guidance said no field is ever a reason to pick
option, cross-thread ones included. That's wrong when a field is written without a lock:optionis always one atomic-sized reference,voptionis a struct that can span more than one word and tear on the write once it does — as PR #20523 found for aPositionfield a text-view listener writes and the project options reactor reads.