Adding:

print('A' * 5000);

To a Fluter project and then running it causes a hang (around 45 seconds on my machine) for the print. Larger messages take many minutes.

The time is being spent in looking for stack frames:

const frame = this.getStackFrameData(message) || this.getWebStackFrameData(message) || this.getMessageWithUriData(message);

These regexes were modified in the latest release, so it's likely those changes have caused this.