Function findHTTPHeader

findHTTPHeader(headers: Object, headerName: string): string | null
Find the name of an HTTP header (case-insensitively) in a JavaScript object.
Parameters
- headers: Object
  The HTTP headers
- headerName: string
  The target header name, ideally already in lower-case
Returns string | null
The name of the header
Example
```
findHTTPHeader({'User-agent': 'foo'}, 'User-Agent')  // Returns 'User-agent'
findHTTPHeader({}, 'User-Agent')  // Returns undefined
```
- Defined in net_utils.js:228