Hi! I met this problem after finishing "make" process:

escript: exception error: undefined function counters:new/2
in function emqtt_bench:init/0 (/app/install/emqtt_benchmark/emqtt-bench/src/emqtt_bench.erl, line 176)
in call from emqtt_bench:start/2 (/app/install/emqtt_benchmark/emqtt-bench/src/emqtt_bench.erl, line 167)
in call from escript:run/2 (escript.erl, line 758)
in call from escript:start/1 (escript.erl, line 277)
in call from init:start_em/1
in call from init:do_boot/3

I've installed erlang/OTP 21.0 and rebar3.