Implement basic network flow control (#2803)

Co-authored-by: Cameron Gutman <aicommander@gmail.com>

src/platform/linux/misc.cpp

@@ -933,4 +933,21 @@ namespace platf {
 
     return std::make_unique<deinit_t>();
   }
+
+  class linux_high_precision_timer: public high_precision_timer {
+  public:
+    void
+    sleep_for(const std::chrono::nanoseconds &duration) override {
+      std::this_thread::sleep_for(duration);
+    }
+
+    operator bool() override {
+      return true;
+    }
+  };
+
+  std::unique_ptr<high_precision_timer>
+  create_high_precision_timer() {
+    return std::make_unique<linux_high_precision_timer>();
+  }
 }  // namespace platf