API: Filter errors on occurences with a specific custom context

[nickvleeuwen]

We have a multi-tenant(client) application, when an error occurs we send the name of the client as 'custom context' so we can Identify on what client the error occurred. It would be nice if I could filter errors on occurences that have a specific 'custom context' key/client, or in my case a specific client. That way we can have an overview what errors happen per client.