assistant: Add health telemetry (#19928)

This PR adds a bit of telemetry for Anthropic models, in order to
understand model health. With this logging, we can monitor and diagnose
dips in performance, for example due to model rollouts.

Release Notes:

- N/A

---------

Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/assistant/src/context.rs

@@ -24,6 +24,7 @@ use gpui::{
 
 use language::{AnchorRangeExt, Bias, Buffer, LanguageRegistry, OffsetRangeExt, Point, ToOffset};
 use language_model::{
+    logging::report_assistant_event,
     provider::cloud::{MaxMonthlySpendReachedError, PaymentRequiredError},
     LanguageModel, LanguageModelCacheConfiguration, LanguageModelCompletionEvent,
     LanguageModelImage, LanguageModelRegistry, LanguageModelRequest, LanguageModelRequestMessage,
@@ -1955,6 +1956,7 @@ impl Context {
                                     });
 
                                 match event {
+                                    LanguageModelCompletionEvent::StartMessage { .. } => {}
                                     LanguageModelCompletionEvent::Stop(reason) => {
                                         stop_reason = reason;
                                     }
@@ -2060,23 +2062,28 @@ impl Context {
                         None
                     };
 
-                    if let Some(telemetry) = this.telemetry.as_ref() {
-                        let language_name = this
-                            .buffer
-                            .read(cx)
-                            .language()
-                            .map(|language| language.name());
-                        telemetry.report_assistant_event(AssistantEvent {
+                    let language_name = this
+                        .buffer
+                        .read(cx)
+                        .language()
+                        .map(|language| language.name());
+                    report_assistant_event(
+                        AssistantEvent {
                             conversation_id: Some(this.id.0.clone()),
                             kind: AssistantKind::Panel,
                             phase: AssistantPhase::Response,
+                            message_id: None,
                             model: model.telemetry_id(),
                             model_provider: model.provider_id().to_string(),
                             response_latency,
                             error_message,
                             language_name: language_name.map(|name| name.to_proto()),
-                        });
-                    }
+                        },
+                        this.telemetry.clone(),
+                        cx.http_client(),
+                        model.api_key(cx),
+                        cx.background_executor(),
+                    );
 
                     if let Ok(stop_reason) = result {
                         match stop_reason {
@@ -2543,7 +2550,7 @@ impl Context {
                     let mut messages = stream.await?;
 
                     let mut replaced = !replace_old;
-                    while let Some(message) = messages.next().await {
+                    while let Some(message) = messages.stream.next().await {
                         let text = message?;
                         let mut lines = text.lines();
                         this.update(&mut cx, |this, cx| {