public static int GetHashCode <T>(ref T val) where T : struct
 {
     #if !UNITY_CSHARP_TINY
     var typeInfo = TypeManager.GetTypeInfo <T>().FastEqualityTypeInfo;
     return(FastEquality.GetHashCode(ref val, typeInfo));
     #else
     return(EqualityHelper <T> .Hash(val));
     #endif
 }