* do we need a sort of bus for application data
* do we need a dictionary for our applications like Apple does. We could easily hook into this and this is the model we need to follow. Following the model of apple applications the dictionary is what the REST URI should attach to. Not creating custom logic in the resource code.
* how many of our REST services do not map directory to a method in the application interface?

- an example of adding js

## HTTPX { #httpx }

Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath.

### Threads

#### Application's calling thread

The application-layer must block on writing I/O. We can't return from a write until we've pushed its bytes onto the socket. Otherwise, if the write fails we are unable to deliver its IOException to the application. We would have told the application layer that the write succeeded, but it didn't!

    * Will have the best performance, as it doesn't have much extra code apart from the server itself.
    * You wouldn't write an application in Uvicorn directly. That would mean that your code would have to include more or less, at least, all the code provided by Starlette (or **FastAPI**). And if you did that, your final application would have the same overhead as having used a framework and minimizing your app code and bugs.

### Multiple Applications { #multiple-applications }

In the same server (or servers), there could be **multiple applications**, for example, other API programs or a database.

     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

### Bigger Errors - Crashes { #bigger-errors-crashes }

Nevertheless, there might be cases where we write some code that **crashes the entire application** making Uvicorn and Python crash. 💥

                    "summary": "Post Root",
                    "operationId": "foo_post_root",
                    "requestBody": {
                        "content": {
                            "application/json": {
                                "schema": {
                                    "$ref": "#/components/schemas/Body_foo_post_root"
                                }
                            }