AMQPHelpers.Adapter.get_next_delivery_tag
You're seeing just the callback
get_next_delivery_tag, go back to AMQPHelpers.Adapter module for more information.
Link to this callback
get_next_delivery_tag(channel)
Specs
get_next_delivery_tag(channel :: AMQP.Channel.t()) :: non_neg_integer()
Returns the next message sequence number.