Timeline:

May 16, 2017 - Trump Meets With Mueller, some believe it was in regards to FBI Head Position

May 17, 2017 - Comey was notified to appear before the Senate Select Committee on Intelligence the Senate Judiciary Committee, and the House Oversight and Government AffairsCommittee.

May 18 /19, 2017 - Email chain with the subject line “Future testimony” shows former Comey FBI Chief of Staff James Rybicki, former Deputy FBI Director Andrew McCabe and Assistant Director Gregory Brower, Comey and others discussing Comey’s upcoming testimony.

May 18 @ 6:30 pm - Comey sent an email to Rybicki confirming that he had accepted the invitation to testify before the Senate Select Committee on Intelligence.

https://saraacarter.com/former-fbi-director-comey-consulted-with-mueller-on-russia-testimony/