Filter adelay
  Delay one or more audio channels.
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (audio)
adelay AVOptions:
  delays            <string>     ..F.A..... set list of delays for each channel
  all               <boolean>    ..F.A..... use last available delay for remained channels (default false)

This filter has support for timeline through the 'enable' option.

