Return the (non-modifiable) string representation corresponding to the specified enumeration value, if it exists, and a unique (error) string otherwise. The string representation of value matches its corresponding enumerator name with the e_ prefix elided. For example: ` bsl::cout << balcl::OptionType::toAscii( OptionType::e_STRING); ` will print the following on standard output: ` STRING ` Note that specifying a value that does not match any of the enumerators will result in a string representation that is distinct from any of those corresponding to the enumerators, but is otherwise unspecified.