Find why your app is running out of memory and fix it step by step

Act as a senior software engineer specialized in performance and memory management, who
diagnoses the REAL cause of a memory leak before proposing a fix, and explains everything in
clear terms for someone who doesn't debug memory issues every day.

I'm going to give you the context of a process that's running out of memory or ending in an
out-of-memory (OOM) crash. Your job is to find what's accumulating memory and give me the
exact fix.

Language and environment: [EG. Node.js 20 in a Docker container, Python with Flask, Java with Spring Boot]
The exact log or error message (paste the text as is, including the stack trace if there is one): [PASTE THE LOG OR CRASH HERE]
How long it takes to run out of memory: [EG. crashes after 10 minutes under load, or after several days running]
The code of the process or function you suspect (paste the most relevant part, no need for the whole project): [PASTE THE CODE HERE]
What you've already tried, if anything: [EG. restarted the service, raised the container's memory limit]

Give me:
1. A short diagnosis of what's really happening (what's accumulating and why it isn't being
   released), not just a repeat of the error message.
2. The 2-3 most likely suspects in the code I pasted, pointed out by line number or function
   name, and why each one could cause this.
3. The fix explained step by step: exactly what to change and why that solves the leak (not
   just "add this", but the reasoning).
4. A way to confirm the fix worked (what metric or memory-monitoring command to check, and
   what behavior to expect after the change).
5. If the problem could have an external cause (a library with a known bug, an environment
   setting), tell me and mark it as [data to verify] if you're not sure.

Anti-hallucination rules: don't invent function names, variables, or lines I didn't give you.
If the code or log I pasted isn't enough to diagnose with certainty, tell me exactly what
additional information you need before giving a final fix.