If String has N valid hexadecimal characters for conversion, the caller must make sure Buffer is at least \r
N/2 (if N is even) or (N+1)/2 (if N if odd) bytes. \r
\r
+ If either Buffer, BufferSizeInBytes or String is NULL, then ASSERT ().\r
+\r
@param Buffer The output buffer allocated by the caller.\r
@param BufferSizeInBytes On input, the size in bytes of Buffer. On output, it is updated to \r
contain the size of the Buffer which is actually used for the converstion.\r