Set a sleep for async requests

BMA API from Duniter does not handles lots of request at the same time.

With blocks, silkaj is requesting to know the identity of issuer of the block and send a request for all of them at the same time.

It might be Duniter’s anti-spam mechanism which prevents more requests. A sleep of 0.01 seconds between requests solves the issue.

• blocks to get identities
• net:
  • to get leaves
  • to get identities (can’t be checked on Ğ1 because it’s failing before)