Add basic new streaming tail worker types

src/workerd/api/trace.c++

@@ -184,6 +184,10 @@ kj::Maybe<TraceItem::EventInfo> getTraceEvent(jsg::Lock& js, const Trace& trace)
         }
         KJ_UNREACHABLE;
       }
+      KJ_CASE_ONEOF(resume, tracing::Resume) {
+        // Resume events are not used with legacy trace
+        KJ_UNREACHABLE;
+      }
       KJ_CASE_ONEOF(custom, tracing::CustomEventInfo) {
         return kj::Maybe(jsg::alloc<TraceItem::CustomEventInfo>(trace, custom));
       }

src/workerd/io/io-context.c++

@@ -202,7 +202,7 @@ IoContext::IncomingRequest::IoContext_IncomingRequest(kj::Own<IoContext> context
     kj::Own<IoChannelFactory> ioChannelFactoryParam,
     kj::Own<RequestObserver> metricsParam,
     kj::Maybe<kj::Own<WorkerTracer>> workerTracer,
-    kj::Rc<tracing::InvocationSpanContext> invocationSpanContext)
+    tracing::InvocationSpanContext invocationSpanContext)
     : context(kj::mv(contextParam)),
       metrics(kj::mv(metricsParam)),
       workerTracer(kj::mv(workerTracer)),

src/workerd/io/io-context.h

@@ -111,7 +111,7 @@ class IoContext_IncomingRequest final {
       kj::Own<IoChannelFactory> ioChannelFactory,
       kj::Own<RequestObserver> metrics,
       kj::Maybe<kj::Own<WorkerTracer>> workerTracer,
-      kj::Rc<tracing::InvocationSpanContext> invocationSpanContext);
+      tracing::InvocationSpanContext invocationSpanContext);
   KJ_DISALLOW_COPY_AND_MOVE(IoContext_IncomingRequest);
   ~IoContext_IncomingRequest() noexcept(false);
 
@@ -163,7 +163,7 @@ class IoContext_IncomingRequest final {
 
   // The invocation span context is a unique identifier for a specific
   // worker invocation.
-  kj::Rc<tracing::InvocationSpanContext>& getInvocationSpanContext() {
+  tracing::InvocationSpanContext& getInvocationSpanContext() {
     return invocationSpanContext;
   }
 
@@ -176,7 +176,7 @@ class IoContext_IncomingRequest final {
   // The invocation span context identifies the trace id, invocation id, and root
   // span for the current request. Every invocation of a worker function always
   // has a root span, even if it is not explicitly traced.
-  kj::Rc<tracing::InvocationSpanContext> invocationSpanContext;
+  tracing::InvocationSpanContext invocationSpanContext;
 
   bool wasDelivered = false;