I received a phone call from Constellation Energy on an evening asking whether I was available for an onsite interview the next morning. I really needed more time, so I asked if it could be postponed to a later date and that this was too sudden. The HR said she can move it to a date couple of working days later, and they are not going to interview for many days for this position - I had no choice to accept to get interviewed the next day with one night to prepare. The day started early, and I went through five rounds of interviews. Only the second was heavily technical and the rest of the rounds were full of questions from my resume.