It cannot be a better C. You cannot implement exceptions in it using set jump for example, but the biggest problem is memory management. You can't implement your own arena allocator in golang.
To be fair, you don't need to implement exceptions in golang because they already exist in the language, they're just called panics
I've drastically sped up commercial shipping C code by implementing arena allocators and Go is my daily driver and it's not clear to me why you're making this claim.