You're seeing just the function call_nolink, go back to AMQPHelpers.RPC module for more information.
Link to this function

call_nolink(adapter \\ Adapter, supervisor, connection, exchange, routing_key, payload, options \\ [])


Executes a remote procedure call without linking to the calling process.

Like call/6 but it does not link the waiting process to the calling process. Check Task.Supervisor for more information.