Module Trace_subscriber.CallbacksSource

Callbacks used for subscribers.

Each subscriber defines a set of callbacks, for each possible tracing event. These callbacks take a custom state that is paired with the callbacks in Subscriber.t.

To use a default implementation for some callbacks, use:

  module My_callbacks = struct
    type st = …

    include Trace_subscriber.Callbacks.Dummy

    let on_init (state:st) ~time_ns : unit = …

    (* … other custom callbacks … *)
  end

NOTE: the trace_id passed alongside manual spans is guaranteed to be at least 64 bits.