title: Does tbb::concurrent_unordered_map::unsafe_erase invalidate any existing iterators?
body: <p>I see that <code>tbb::concurrent_unordered_map</code> hews pretty close to <code>std::unordered_map</code> while being safe for concurrency. I also know that <code>unsafe_erase</code> is not concurrent-safe with <code>insert</code> etc. The iterator docs also state that any existing iterators are still valid with <code>insert</code>, <code>find</code> etc.</p>
  
  <p>The question is, <strong>does <code>unsafe_erase</code> invalidate any other iterator than the one it is asked to erase?</strong></p>
  
  <p><code>std::unordered_map</code> and <code>std::map</code> certainly have this behavior, but it's not specified in the <code>concurrent_unordered_map</code> docs anywhere.</p>