[exec] 
     [exec] Failures:
     [exec] 
     [exec]   1) FFI::Function can wrap a blocking function
     [exec]      Failure/Error: expect(Time.now - time).to be >= 2
     [exec]      NameError:
     [exec]        uninitialized constant RSpec::Matchers::BuiltIn::Be
     [exec]      # ./spec/ffi/function_spec.rb:71:in `block in (root)'
     [exec] 
     [exec] Finished in 21.64 seconds
     [exec] 4843 examples, 1 failure
     [exec] 
     [exec] Failed examples:
     [exec] 
     [exec] rspec ./spec/ffi/function_spec.rb:65 # FFI::Function can wrap a blocking function