Function appears to execute with no errors, but externally appears to fails

I am trying to call a function with an HttpTrigger from Postman (and/or Fiddler). The function executes with no errors, but in Postman, I only see a 500.

#### Investigative information

Please provide the following:

- Function App version (1.0 or 2.0-beta): 2.0-beta
- Environment: local
- Microsoft.NET.Sdk.Functions: 1.0.13

#### Repro steps

1. Create a function with the following:

```csharp
[FunctionName("PostList")]
public static async Task Post(
[HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "lists")]HttpRequest req,
TraceWriter log)
{
try
{
return new CreatedAtRouteResult(new { id = 1 }, null);
}
catch(Exception e)
{
return new BadRequestResult();
}
}
```

2. Set a breakpoint at both return statements
3. Run with debugging
4. Using Postman (or Fiddler), execute a POST on "http://localhost:7071/api/lists"
5. The first breakpoint is hit, second is not

#### Expected behavior

Upon finishing execution of the function, Postman should receive a 200.

#### Actual behavior

Postman receives a 500 instead.

#### Related information

* Programming language used: C#

Reproduce the issue locally with the supplied C# HttpTrigger, debugger breakpoints, and POST request to http://localhost:7071/api/lists. Start by tracing the response handling after CreatedAtRouteResult is returned; done means the function completes without an error and Postman receives the expected successful response instead of HTTP 500.

Written by the indexing model from the issue text.