Have you considered Nim? You can achieve some really high performance with it[1]. Since you've considered Rust, Go, C and even Pony, Nim should really be on your list.
Also why is evey immature native language considered, but the two speed demon languages without garbage collection - ISPC and C++ - are nowhere to be found?
1 - See httpbeast in the latest round of the Techempower benchmarks: https://www.techempower.com/benchmarks/#section=data-r17&hw=...