feat: Regex on Main Thread profiling issue

[armcknight]

Loads a large text file from disk into a string in memory, starts a manual transaction, and then searches through the string with a regex. See the issue it creates: https://demo.sentry.io/issues/4498267724/?project=6249899&query=is%3Aunresolved+se%3Aandrewmcknight&referrer=issue-stream&statsPeriod=14d&stream_index=0

Here's how you can trigger it:

closes #28

[kpujjigit]

Verified Functional