fix: Remove overwriting of TTFT and RTTFT in openai streaming wrapper

Author: akash-vijay-kv

src/instrumentation/openai/wrappers.ts

@@ -186,15 +186,29 @@ abstract class BaseStreamHandler {
 
   protected finalizeSpan(code: SpanStatusCode): void {
     if (code === SpanStatusCode.OK) {
-      finalizeSpanSuccess(
+      setResponseAttributes(
         this.span,
         this.completeResponse as Record<string, unknown>,
       );
-    } else {
-      recordSpanTiming(this.span, SpanAttributes.LLM_RESPONSE_DURATION);
-      this.span.setStatus({ code });
-      this.span.end();
     }
+    recordSpanTiming(this.span, SpanAttributes.LLM_RESPONSE_DURATION);
+    // Only set TTFT at finalize when no content was detected during
+    // streaming (degenerate case). When streaming produced content,
+    // TTFT was already recorded in processChunk on the first chunk.
+    if (!this.firstContentRecorded) {
+      recordSpanTiming(
+        this.span,
+        SpanAttributes.LLM_PERFORMANCE_TIME_TO_FIRST_TOKEN,
+        { recordEventTimestamp: true },
+      );
+      recordSpanTiming(
+        this.span,
+        SpanAttributes.LLM_PERFORMANCE_RELATIVE_TIME_TO_FIRST_TOKEN,
+        { useRootSpan: true },
+      );
+    }
+    this.span.setStatus({ code });
+    this.span.end();
   }
 }