Function miner::find_solution

pub fn find_solution<T>(
    block: &BlockTemplate, 
    coinbase_transaction_builder: T, 
    max_extranonce: U256
) -> Option<Solution> where
    T: CoinbaseTransactionBuilder, 

Simple bitcoin cpu miner.

First it tries to find solution by changing block header nonce. Once all nonce values have been tried, it increases extranonce. Once all of them have been tried (quite unlikely on cpu ;), and solution still hasn't been found it returns None. It's possible to also experiment with time, but I find it pointless to implement on CPU.