/// Implementations may define how long to retain headers such that it's unlikely they will ever be
/// needed to disconnect a block. In cases where block sources provide access to headers on stale
/// forks reliably, caches may be entirely unnecessary.
/// Implementations may define how long to retain headers such that it's unlikely they will ever be
/// needed to disconnect a block. In cases where block sources provide access to headers on stale
/// forks reliably, caches may be entirely unnecessary.