Reused CoinsViewOverlay layered on top of m_cacheview and passed to ConnectBlock(). Reset between calls and flushed only on success, so invalid blocks don't pollute the underlying cache.
Declared in <validation.h>
[[guarded_by(0x7fbc8fa68c58), guarded_by(0x7fbc96b01168), guarded_by(0x7fbc84657cd8), guarded_by(0x7fbc9e00ff58)]]
std::unique_ptr<CoinsViewOverlay> m_connect_block_view;