fix(response-handling): handle empty SSE lines and "ping" events #97

Previously, the response body callback would crash when encountering an empty line followed by a non-null SSE instance, or when receiving a "ping" event. This commit adds a check to handle both scenarios gracefully by ignoring the "ping" events and resetting the SSE instance when an empty line is received. This ensures the stability and reliability of the response handling logic.

Author: phodal

src/main/kotlin/cc/unitmesh/devti/llms/azure/ResponseBodyCallback.kt

@@ -64,7 +64,12 @@ class ResponseBodyCallback(private val emitter: FlowableEmitter<SSE>, private va
                 sse = when {
                     line!!.startsWith("data:") -> {
                         val data = line!!.substring(5).trim { it <= ' ' }
-                        SSE(data)
+                        //  data: ping - 2024-03-05 02:07:20.310586
+                        if (data.startsWith("ping") || data.startsWith(" ping")) {
+                            null
+                        } else {
+                            SSE(data)
+                        }
                     }
 
                     line == "" && sse != null -> {