Callback
    √ should create a C function pointer from a JS function
    √ should be invokable by an ffi'd ForeignFunction (119ms)
    √ should work with a "void" return type (113ms)
    √ should not call "set()" of a pointer type (117ms)
    √ should throw an Error when invoked through a ForeignFunction and throws (130ms)
    √ should throw an Error with a meaningful message when a type's "set()" throws (88ms)
    - should throw an Error when invoked after the callback gets garbage collected
    √ should propagate callbacks and errors back from native threads (175ms)
    async
      √ should be invokable asynchronously by an ffi'd ForeignFunction (125ms)
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File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |       0 |        0 |       0 |       0 |                   
----------|---------|----------|---------|---------|-------------------
Command exited with code -1073741819