Compile.WritesSourceCompilation writes, files written by compiling a .cmi, .cmti, .cmt or .mld file to an .odoc file.
As determined by the odoc compile-targets command.
write m cobj ~to_odoc ~o writes the files written by a compilation of cobj to to_odoc to o.
read m file reads the result of a write from file and continues with the files that will be written.