Tarearbol.Pool.defsynch

You're seeing just the macro defsynch, go back to Tarearbol.Pool module for more information.
Link to this macro

defsynch(definition, opts \\ [])

View Source (macro) (since 1.4.0)

Declares a synchronous function with the same name and block, that will be under the hood routed to the free worker to execute. If there is no free worker at the moment, returns :error otherwise returns {:ok, result} tuple.

This function might return any response recognizable by Tarearbol.DynamicManager.response/0.