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(0x7fb95f93ac88), guarded_by(0x7fb96ab6afa8), guarded_by(0x7fb96d9bdfd8), guarded_by(0x7fb9873beb78)]]
std::unique_ptr<CoinsViewOverlay> m_connect_block_view;