Generates valid etkey matching specified pattern.

Usage

> etkeygen C0FFEE
Seeking the matching GUID on 32 threads...
Found: C0FFEEA4EC22600984F2DF6A7294DBCD [0000001002012309041210023074]

> etkeygen F00__________________________F00
Seeking the matching GUID on 32 threads...
Found: F00016236186B9D0323E533B7AC38F00 [0000001002012309041241531463]

Obviously, the more specific pattern is entered, the longer it takes to find the GUID.