Issue 6410 bulk indexing missing index update


    Bulk API: Do not fail whole request on closed index
    
    Changes from comments to @spinscale PR.
    """
    The bulk API request was marked as completely failed,
    in case a request with a closed index was referred in
    any of the requests inside of a bulk one.
    
    Implementation Note: Currently the implementation is a bit more verbose in order to prevent an instanceof check and another cast - if that is fast enough, we could execute that logic only once at the 
    """
    See #6790

can we have documentation for all of those?