Refactor ViewerStreams internals to allow a single list ot tabs

The way that `ViewerStreams` was set up made it hard to mix components that depending on `RSC_CHUNK` together with those that may instead need `RSC_REQUEST` and `RSC_RESPONSE`. The `FlightResponse` component was sort of dictating a split between them.

It needed to change because I wanted to put "Headers" in the same row as everything else, like the parsed chunks and the network graph.

I ended up changing a few other things as well, like removing a bunch of `useMemo` (to make the code simpler, and because the compiler is going to help).

packages/core/src/components/EndTimeContext.tsx

@@ -1,3 +1,68 @@
-import { createContext } from "react";
+import {
+  ReactNode,
+  createContext,
+  useContext,
+  useEffect,
+  useState,
+  useTransition,
+} from "react";
 
-export const EndTimeContext = createContext<number>(Infinity);
+const EndTimeContext = createContext<{
+  endTime: number;
+  visibleEndTime: number;
+  changeEndTime: (value: number) => void;
+  isPending: boolean;
+}>({
+  endTime: Infinity,
+  visibleEndTime: Infinity,
+  changeEndTime: () => {},
+  isPending: false,
+});
+
+export function EndTimeProvider({
+  maxEndTime,
+  children,
+}: {
+  maxEndTime: number;
+  children: ReactNode;
+}) {
+  const [endTime, setEndTime] = useState(Infinity);
+  const [visibleEndTime, setVisibleEndTime] = useState(endTime);
+  const [isPending, startTransition] = useTransition();
+
+  const changeEndTime = (value: number) => {
+    setVisibleEndTime(value);
+    startTransition(() => {
+      setEndTime(value);
+    });
+  };
+
+  useEffect(() => {
+    if (endTime !== maxEndTime) {
+      changeEndTime(maxEndTime);
+    }
+  }, [maxEndTime]);
+
+  return (
+    <EndTimeContext.Provider
+      value={{
+        endTime,
+        visibleEndTime,
+        changeEndTime,
+        isPending,
+      }}
+    >
+      <div>{children}</div>
+    </EndTimeContext.Provider>
+  );
+}
+
+export function useEndTime() {
+  const context = useContext(EndTimeContext);
+
+  if (context === undefined) {
+    throw new Error("useEndTime must be used within a EndTimeContext.Provider");
+  }
+
+  return context;
+}