Read Or Execute

Read or execute a file to get a content stream

If a file is executable, run it, otherwise read it's contents.

Typically this is used for config files that can be either static or executable.

• Options passed in are forwarded to the underlying child_process.spawn or fs.createReadFile.
• Defaults to "utf8" encoding (unless set to null).
• Async-function implementation. Underlying platform promisification via standard mz dependency.