backtrace option fails on macOS

[wlipa]

I have not been able to figure out how to use rbtrace to generate backtraces. It's working for exec (-e) option though.

Process to be traced (last line appears after the rbtrace run):

$ rails s
=> Booting Puma
=> Rails 6.0.3.4 application starting in development 
=> Run `rails server --help` for more startup options
Puma starting in single mode...
* Puma version: 5.1.1 (ruby 2.7.2-p137) ("At Your Service")
*  Min threads: 1
*  Max threads: 1
*  Environment: development
*          PID: 17779
* Listening on http://127.0.0.1:3000
* Listening on http://[::1]:3000
Use Ctrl-C to stop
sendto(18): No buffer space available

Tracing side:

$ rbtrace -p 17779 -b
*** attached to process 17779
*** timed out waiting for eval response
*** detached from process 17779