anchor.diff:  ----
   
   
  -=== How to use it?
  +=== How to use it
   
   Create your contract using the following:
   
  
positive.code: 
  == GSN Bouncers
  
  A *GSN Bouncer* decides which transaction gets approved and which transaction gets rejected. Bouncers are a key concept within GSN. Dapps need Bouncers to prevent malicious users to spend the transactions subsidy.
  
  As we have seen in the Basic Guide, in order to use GSN, your contracts need to extend from GSN Recipient.
  
  
negative.code: ----
  
  We transfer the max amount of tokens assuming that the call will use all the gas available.
  Then, in the _postRelayedCall method, we calculate the actual amount - including the implementation and ERC transfers - and refund the difference.
  
  [source,solidity]
  ----
  