need custom lookahead

[arronzhang]

I generated 100 btc addresses and transferred. It was found that only the first 25 could be signed. It is should be restricted by DEFAULT_LOOKAHEAD, and no configurable code was found. Is there any other way?

[arronzhang]

We can create the address by AddressIndex::New first to fix it.

for _ in 0..100 {
        wallet.try_get_address(AddressIndex::New)?;
    }

[LLFourn]

I think #1250 will allow you to configure DEFAULT_LOOKAHEAD