Signature object is not sorted according to query

Not sure if it’s a bug or by design, but why ‘signature’ returns fields not in the right order?

e.g

N1QL query is
SELECT hiredate,employee_no , department.name , salary, manager, jobtitle FROM …

the signature is:

{
“manager”:“json”,
“name”:“json”,
“employee_no”:“json”,
“jobtitle”:“json”,
“hiredate”:“json”,
“salary”:“json”
}

Expected result:

{
“hiredate”:“json”,
“employee_no”:“json”,
“name”:“json”,
“salary”:“json”,
“manager”:“json”,
“jobtitle”:“json”
}

It is design. The results are returned in key-value pair and it doesn’t matter which order it is present in projection. The results are sorted by key so that it can be easily spot in the document.