// constructors
 internal BsonDocumentReaderBookmark(
     BsonReaderState state,
     BsonType currentBsonType,
     string currentName,
     BsonDocumentReaderContext context,
     BsonValue currentValue)
     : base(state, currentBsonType, currentName)
 {
     _context = context.Clone();
     _currentValue = currentValue;
 }
 // constructors
 internal BsonDocumentReaderBookmark(
     BsonReaderState state,
     BsonType currentBsonType,
     string currentName,
     BsonDocumentReaderContext context,
     BsonValue currentValue)
     : base(state, currentBsonType, currentName)
 {
     _context      = context.Clone();
     _currentValue = currentValue;
 }
 // internal methods
 internal BsonDocumentReaderContext CloneContext()
 {
     return(_context.Clone());
 }