Adapt a create_media_buy request for a v2 server.
Strips v3-only top-level fields, converts brand → brand_manifest, derives
buyer_ref (top-level + per-package) from context.buyer_ref or
idempotency_key, and adapts packages.
v2.5 requires buyer_ref as the buyer's reference for THIS media buy,
top-level + per-package. v3 removed the top-level field and moved buyer
correlation into context.buyer_ref; idempotency_key carries the same
client-controlled-unique-identity semantics. Preferring the caller's
context.buyer_ref before falling back to idempotency_key preserves the
buyer's stable reference on the wire when they provided one, and still
satisfies v2.5 dedupe on replay when they did not. Caller-supplied
top-level buyer_ref (if any) always wins.
Adapt a create_media_buy request for a v2 server. Strips v3-only top-level fields, converts brand → brand_manifest, derives
buyer_ref(top-level + per-package) fromcontext.buyer_reforidempotency_key, and adapts packages.v2.5 requires
buyer_refas the buyer's reference for THIS media buy, top-level + per-package. v3 removed the top-level field and moved buyer correlation intocontext.buyer_ref;idempotency_keycarries the same client-controlled-unique-identity semantics. Preferring the caller'scontext.buyer_refbefore falling back toidempotency_keypreserves the buyer's stable reference on the wire when they provided one, and still satisfies v2.5 dedupe on replay when they did not. Caller-supplied top-levelbuyer_ref(if any) always wins.