chore: update README

Author: fern-support

README.md

@@ -0,0 +1,87 @@
+# Vapi C# Library
+
+[![fern shield](https://img.shields.io/badge/%F0%9F%8C%BF-Built%20with%20Fern-brightgreen)](https://buildwithfern.com?utm_source=github&utm_medium=github&utm_campaign=readme&utm_source=https%3A%2F%2Fgithub.com%2FVapiAI%2Fserver-sdk-csharp)
+[![nuget shield](https://img.shields.io/nuget/v/Vapi.Net)](https://nuget.org/packages/Vapi.Net)
+
+The Vapi C# library provides convenient access to the Vapi API from C#.
+
+## Installation
+
+```sh
+nuget install Vapi.Net
+```
+
+## Usage
+
+Instantiate and use the client with the following:
+
+```csharp
+using Vapi.Net;
+
+var client = new VapiClient("TOKEN");
+await client.Calls.CreateAsync(new CreateCallDto());
+```
+
+## Exception Handling
+
+When the API returns a non-success status code (4xx or 5xx response), a subclass of the following error
+will be thrown.
+
+```csharp
+using Vapi.Net;
+
+try {
+    var response = await client.Calls.CreateAsync(...);
+} catch (VapiClientApiException e) {
+    System.Console.WriteLine(e.Body);
+    System.Console.WriteLine(e.StatusCode);
+}
+```
+
+## Advanced
+
+### Retries
+
+The SDK is instrumented with automatic retries with exponential backoff. A request will be retried as long
+as the request is deemed retriable and the number of retry attempts has not grown larger than the configured
+retry limit (default: 2).
+
+A request is deemed retriable when any of the following HTTP status codes is returned:
+
+- [408](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/408) (Timeout)
+- [429](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429) (Too Many Requests)
+- [5XX](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/500) (Internal Server Errors)
+
+Use the `MaxRetries` request option to configure this behavior.
+
+```csharp
+var response = await client.Calls.CreateAsync(
+    ...,
+    new RequestOptions {
+        MaxRetries: 0 // Override MaxRetries at the request level
+    }
+);
+```
+
+### Timeouts
+
+The SDK defaults to a 30 second timeout. Use the `Timeout` option to configure this behavior.
+
+```csharp
+var response = await client.Calls.CreateAsync(
+    ...,
+    new RequestOptions {
+        Timeout: TimeSpan.FromSeconds(3) // Override timeout to 3s
+    }
+);
+```
+
+## Contributing
+
+While we value open-source contributions to this SDK, this library is generated programmatically.
+Additions made directly to this library would have to be moved over to our generation code,
+otherwise they would be overwritten upon the next generated release. Feel free to open a PR as
+a proof of concept, but know that we will not be able to merge it as-is. We suggest opening
+an issue first to discuss with us!
+
+On the other hand, contributions to the README are always very welcome!