[keelerm84]

Config#private_attributes now returns a Set of attribute reference
strings instead of an Array. The :private_attributes option still
accepts any Enumerable, and the SDK converts it to a Set.

LDContext#private_attributes now returns a frozen Set of Reference
objects instead of an Array. The context already stored a Set
internally and copied it to an Array on every call. Private attributes
have no meaningful order or duplicates, so a Set is the correct type.

Code that indexes into the result or calls Array-only methods on it
must change. LDContext#to_h and #to_json still emit privateAttributes
as an Array, so serialized contexts and event payloads do not change.

---

Note

Overview
Breaking change: Config#private_attributes and LDContext#private_attributes now expose Set values instead of Array. The :private_attributes config option still accepts any Enumerable, which the SDK normalizes into a set (deduping entries).

On LDContext, the internal set is frozen after construction, the accessor no longer copies to an array on each call, and equality checks use set comparison directly. ContextFilter stores global private refs in a set and merges them with per-context refs via set union (|) instead of array concatenation.

Wire format unchanged: LDContext#to_h / serialization still emit privateAttributes as an array (private_attributes.to_a). Callers that indexed into or relied on Array-only APIs on the getters must migrate to set-friendly usage.

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