createVercelAISDKTokenUsage incompatible with AI SDK v5

[cvolawless]

Describe the bug
AI SDK v5’s streamText and generateText functions return usage with inputTokens/outputTokens/totalTokens. The LD helper trackVercelAISDKStreamTextMetrics and createVercelAISDKTokenUsage is still looking for promptTokens/completionTokens from v4, so it reads undefined and emits 0.

To reproduce
wrap streamText in trackVercelAISDKStreamTextMetrics - duration metrics are tracked but token use is not

Expected behavior
Token use is appropriately tracked in Vercel AI SDK v4 and v5

Logs
n/a

SDK version
"@launchdarkly/server-sdk-ai": "^0.11.0"

[jsonbailey]

Thanks for reporting this @cvolawless. Version 0.11.4 should now properly report tokens with either Vercel v4 or v5. Let us know if you have any issues with the update.