Function LLVMRustCoverageWriteFilenamesToBuffer 

pub(crate) unsafe extern "C" fn LLVMRustCoverageWriteFilenamesToBuffer(
    Filenames: *const *const c_uchar,
    FilenamesLen: size_t,
    Lengths: *const size_t,
    LengthsLen: size_t,
    BufferOut: &RustString,
)

A list of pointer-length strings is passed as two pointer-length slices, one slice containing pointers and one slice containing their corresponding lengths. The implementation will check that both slices have the same length.