Documentation Revamp

Co-authored-by: jbdoumenjou <jb.doumenjou@gmail.com>

docs/content/middlewares/buffering.md

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+# Buffering
+
+How to Read the Request before Forwarding It
+{: .subtitle }
+
+![Buffering](../assets/img/middleware/buffering.png)
+
+The Buffering middleware gives you control on how you want to read the requests before sending them to services.
+
+With Buffering, Traefik reads the entire request into memory (possibly buffering large requests into disk), and rejects requests that are over a specified limit.
+
+This can help services deal with large data (multipart/form-data for example), and can minimize time spent sending data to a service.
+
+## Configuration Examples
+
+??? example "File -- Sets the maximum request body to 2Mb"
+    
+    ```toml
+    [Middlewares]
+      [Middlewares.2Mb-limit.buffering]
+          maxRequestBodyBytes = 250000
+    ``` 
+
+??? example "Docker -- Buffers 1Mb of the request in memory, then writes to disk"
+
+    ```yaml
+    a-container:
+      image: a-container-image 
+        labels:
+          - "traefik.middlewares.1Mb-memory.buffering.memRequestBodyBytes=125000",
+    ```
+
+## Configuration Options
+
+### maxRequestBodyBytes
+
+With the `maxRequestBodyBytes` option, you can configure the maximum allowed body size for the request (in Bytes).
+
+If the request exceeds the allowed size, the request is not forwarded to the service and the client gets a `413 (Request Entity Too Large) response.
+
+### memRequestBodyBytes
+
+You can configure a thresold (in Bytes) from which the request will be buffered on disk instead of in memory with the `memRequestBodyBytes` option. 
+
+### maxResponseBodyBytes
+
+With the `maxReesponseBodyBytes` option, you can configure the maximum allowed response size from the service (in Bytes).
+
+If the response exceeds the allowed size, it is not forwarded to the client. The client gets a `413 (Request Entity Too Large) response` instead.
+
+### memResponseBodyBytes
+
+You can configure a thresold (in Bytes) from which the response will be buffered on disk instead of in memory with the `memResponseBodyBytes` option. 
+
+### retryExpression
+
+You can have the Buffering middleware replay the request with the help of the `retryExpression` option.
+
+!!! example "Retries once in case of a network error"
+    
+    ```
+    retryExpression = "IsNetworkError() && Attempts() < 2"
+    ```
+    
+Available functions for the retry expression are:
+
+- `Attempts()` number of attempts (the first one counts)
+- `ResponseCode()` response code of the service
+- `IsNetworkError()` - if the response code is related to networking error