Enum of isolation levels. This enum exists because Java annotations do not support null default values - so we need
to add the DEFAULT level which means - do not specify an isolation level.
Returns the enum constant of this type with the specified name.
The string must match exactly an identifier used to declare an
enum constant in this type. (Extraneous whitespace characters are
not permitted.)
Parameters:
name - the name of the enum constant to be returned.