These exceptions are raised when a client submits a malformed request.

These errors are caught by Aphront itself and occur too early or too fundamentally in request handling to allow the request to route to a controller or survive to normal processing.

These exceptions can be made "unlogged", which will prevent them from being logged. The intent is that errors which are purely the result of client failure and of no interest to the server can be raised silently to avoid cluttering the logs with client errors that are not actionable.