awsLambdaHandler set inside getLambdaSupportsStreaming. This closes a gap where non-Node builders (e.g. @vercel/redwood) constructed NodejsLambda with awsLambdaHandler but no explicit supportsResponseStreaming, causing finalizeLambda to silently flip streaming on for AWS custom handlers. With the gate now enforced centrally in finalizeLambda, the equivalent @vercel/node build-time check from #16266 is consolidated away — all builders go through the same gate.Fetched May 10, 2026