Performance Comparison of Existence Test for a Large Set using Big One Line If vs Else Ifs vs Dictionary Vs Fall Through Case Statement

Below is C# (Sharp) code compares performance for element existence in a large non-sequential set (only 312 elements) using in variety of typical code structures which are;

1. one line IF (with  ORs) 
2. multi-line Else Ifs 
3. Fall Through Case Statement 
4. Dictionary with Initialization Time
5. Dictionary Lookup on Key, no init time
6. Dictionary Lookup on Value, no init time

The live C# Code example below check's if a character is a vowel from a set of 312 Unicode vowels extending to Latin-Supplement Unicode code point.

Note: Under the hood C# compiler creates a dictionary for 6 or more case statements
https://youtu.be/1lnwO63LhRI?t=871

The results are rather surprising!