That's not true. From a legal standpoint asking someone to do something for you is the same as doing it yourself. Except you've created an additional count of conspiracy.
Did he simply give the memo to a friend, or did he give it with explicit instructions? I don’t think Comey is the sharpest knife in the drawer, but he’s not stupid enough to commit a crime and then describe it on national TV. If he did this in a certain way, take it to the bank that it was in order to skirt any applicable law.
Sort of like hiring a hit man.
I wonder if the fact that Comey said he leaked the memo to try and spur the appointment of a special prosecutor has any legal implications? He tried to influence a high level government decision by leaking uncorroborated information. If not illegal, it's definitely dirty pool and low life behavior.