function _findIfCallbackIsUnary (callback) {
  if (callback.length !== 1) return false

  const callbackStr = callback.toString()
  // Check if the callback function uses `arguments`
  if (/arguments/.test(callbackStr)) return false

  // Extract the parameters of the callback function
  const paramsStr = callbackStr.match(/\(.*?\)/)
  // Check if the callback function uses rest parameters
  if (/\.\.\./.test(paramsStr)) return false
  return true
}
Determines if a given callback function is unary (i.e., takes exactly one argument).

This function checks the following conditions to determine if the callback is unary:
1. The callback function should have exactly one parameter.
2. The callback function should not use the `arguments` object.
3. The callback function should not use rest parameters (`...`).
If in doubt, this function shall return `false` to be safe

@param {Function} callback - The callback function to be checked.
@returns {boolean} - Returns `true` if the callback is unary, otherwise `false`.