(mongodb >=1.15.0)
MongoDB\Driver\ClientEncryption::deleteKey — Deletes a key document
   Removes the key document with the given UUID keyId
   from the key vault collection.
  
keyIdA MongoDB\BSON\Binary instance with subtype 4 (UUID) identifying the key document.
   Returns the result of the internal deleteOne operation on
   the key vault collection.
  
