RCLConsensus::acquireLedger

Attempt to acquire a specific ledger.

boost::optional< RCLCxLedger >
acquireLedger(
    LedgerHash const& ledger);

If not available, asynchronously acquires from the network.

Name	Description
`ledger`	The ID/hash of the ledger acquire

Optional ledger, will be seated if we locally had the ledger