closure-compiler compiling an empty method

gistfile1.txt

>> require 'closure-compiler'
=> true
>> require 'benchmark'
=> true
>> puts Benchmark.measure { Closure::Compiler.new.compile 'function foo() {}' }
  0.000000   0.010000   2.600000 (  1.571835)
=> nil
>> puts Benchmark.measure { Closure::Compiler.new.compile 'function foo() {}' }
  0.000000   0.000000   2.630000 (  1.624686)
=> nil

^ 2.6 seconds to compress that. Seriously?

For the record, I understand that's the time it takes to 
call out to Java to execute the .jar file. Still, for what 
I'm building, it's an awful lot expensive.

EDIT: Solution so far → https://github.com/rgrove/jsmin