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

consume(adapter \\ Adapter, channel, queue, consumer \\ nil, options \\ [])


consume(module(), AMQP.Channel.t(), String.t(), pid() | nil, keyword()) ::
  {:ok, String.t()} | AMQP.Basic.error()

Registers a queue consumer process.

Like AMQP.Basic.consume/4 but enforces options which play nicely with a high throughput scenario.