Update FastAPI Response Streaming example

Author: bnusunny

examples/fastapi-response-streaming-zip/README.md

@@ -2,7 +2,7 @@
 
 This example shows how to use Lambda Web Adapter to run a FastAPI application with response streaming via a Function URL.
 
-### How does it work?
+## How does it work?
 
 We add Lambda Web Adapter layer to the function and configure wrapper script.
 
@@ -14,7 +14,7 @@ We add Lambda Web Adapter layer to the function and configure wrapper script.
 
 To get more information of Wrapper script, please read Lambda documentation [here](https://docs.aws.amazon.com/lambda/latest/dg/runtimes-modify.html#runtime-wrapper).
 
-This is the resource for Lambda function. The function urls's invoke mode is configured as "RESPONSE_STREAM", and Lambda environment variable "AWS_LWA_INVOKE_MODE" is set to "response_stream". 
+This is the resource for Lambda function. The function urls's invoke mode is configured as "RESPONSE_STREAM", and Lambda environment variable "AWS_LWA_INVOKE_MODE" is set to "response_stream".
 
 ```yaml
   FastAPIFunction:
@@ -36,17 +36,17 @@ This is the resource for Lambda function. The function urls's invoke mode is con
         InvokeMode: RESPONSE_STREAM
 ```
 
-### Build and Deploy
+## Build and Deploy
 
 Run the following commands to build and deploy the application to lambda.
 
 ```bash
 sam build --use-container
 sam deploy --guided
 ```
-When the deployment completes, take note of FastAPI's Value. It is the API Gateway endpoint URL.
 
-### Verify it works
+When the deployment completes, take note of FastAPI's Value. It is the API Gateway endpoint URL.
 
-Open FastAPI's URL in a browser, you should see "This is streaming from Lambda" streams back 10 times. 
+## Verify it works
 
+Open FastAPI's URL in a browser, you should see "This is streaming from Lambda" streams back character by character.

examples/fastapi-response-streaming-zip/app/main.py

@@ -6,11 +6,12 @@
 
 
 async def streamer():
-    for i in range(10):
-        await asyncio.sleep(1)
-        yield b"This is streaming from Lambda \n"
+    message = "This is streaming from Lambda!\n"
+    for char in message:
+        yield char
+        await asyncio.sleep(0.1)
 
 
 @app.get("/")
 async def index():
-    return StreamingResponse(streamer(), media_type="text/plain; charset=utf-8")
+    return StreamingResponse(streamer(), media_type="text/html")