Block builder used to iterate mempool chunks in mining order while assembling a block.
Declared in <txmempool.h>
[[guarded_by(0x7f95135d1598), guarded_by(0x7f9501b10978), guarded_by(0x7f950ec76b68), guarded_by(0x7f9525ea68b8), guarded_by(0x7f9515095ff8), guarded_by(0x7f950826a298), guarded_by(0x7f94f856d9a8), guarded_by(0x7f9513c57b98)]]
mutable
std::unique_ptr<TxGraph::BlockBuilder> m_builder;