Inject parameter tracer into one function

## Usage

inject_tracer(f)

## Arguments

f

A function (that is, an object of class "function", and not a character string).

## Value

Nothing (will error on fail).

## Note

The tracer is defined in the internal get_types function. This uses an options variable defined on package load for the current tempdir, defining a single location where all traced values are dumped. This is done via options to allow both multi-threaded function calls and calls via callr to be traced.