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(0x7fd753b9e4c8), guarded_by(0x7fd74da5ff98), guarded_by(0x7fd74aa93068), guarded_by(0x7fd75311d3f8)]]
std::unique_ptr<CoinsViewOverlay> m_connect_block_view;