Analyzer: Suggested DocumentDB Use Pattern

**Conditions to Trigger Analyzer**
Within a `[Function]`-decorated method, where a new DocumentClient is instantiated..

```csharp
public static class CosmosDBWrong
{
[FunctionName("CosmosDBWrong")]
public static async Task Run(
[HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");

string endpointUri = "testCosmosDB";
string primaryKey =


var docDBClient = new DocumentClient(new Uri(endpointUri), primaryKey, new ConnectionPolicy()
{
MaxConnectionLimit = 100,
ConnectionMode = ConnectionMode.Gateway,
ConnectionProtocol = Protocol.Tcp,
RetryOptions = new RetryOptions() { MaxRetryAttemptsOnThrottledRequests = 3, MaxRetryWaitTimeInSeconds = 60 }
});

string responseMessage = "Hello from CosmosDB";

return new OkObjectResult(responseMessage);
}
}
```

**Diagnostic Level**
Warning

**How to Fix Violations**
1. Lazy static instantiation outside of [Function] method:

```csharp
using Microsoft.Azure.Documents.Client;

private static Lazy lazyClient = new Lazy(InitializeDocumentClient);
private static DocumentClient documentClient => lazyClient.Value;

private static DocumentClient InitializeDocumentClient()
{
// Perform any initialization here
var uri = new Uri("example");
var authKey = "authKey";

return new DocumentClient(uri, authKey);
}

public static async Task Run(string input)
{
Uri collectionUri = UriFactory.CreateDocumentCollectionUri("database", "collection");
object document = new { Data = "example" };
await documentClient.UpsertDocumentAsync(collectionUri, document);

// Rest of function
}
```

2. Inject DocumentClient using DI, ex. https://github.com/jeffhollan/functions-csharp-cosmosdb-di

**Whether to Supply Codefix**
Yes for 1, if possible for 2.

**Associated Documentation**
https://docs.microsoft.com/en-us/azure/azure-functions/manage-connections

**When to Suppress Analyzer Rule**
This rule should not be suppressed.

No source files or tests are named. Start by locating the analyzer rules for [Function]-decorated methods and DocumentClient construction, then review the linked Azure Functions connection-management documentation; done means a warning is reported and the requested lazy-static or DI guidance is represented in the analyzer/codefix behavior.

Written by the indexing model from the issue text.