The halogen atom of an alkyl halide can be replaced by the hydrogen atom bonded to tin

Question:

The halogen atom of an alkyl halide can be replaced by the hydrogen atom bonded to tin in tributyltin hydride (Bu3SnH). The process, called dehalogenation, is a radical reaction, and it can be initiated by AIBN (2,29-azobisisobutyronitrile). AIBN decomposes to form nitrogen gas and two isobutyronitrile radicals, which initiate the reaction. Write a mechanism for the reaction.