Not all output reaching terminal before exit

[matt2e]

Output from FTL is not always reaching the terminal. This seems to happen when larger text is printed right before exiting.
I think I'm seeing this when trying to get a schema diff, but instead of seeing the diff i expected, I get nothing or a partial result.

Steps to repro:

• Add these lines to cmd_schema_diff.go.66:

fmt.Printf("=====\nbefore\n=====\n%v\n", current)
fmt.Printf("=====\nafter\n=====\n%v\n", other)

• Start up FTL:ftl dev --recreate
• In another terminal window, run ftl schema diff

Expected behaviour:

• We would get a wall of text showing before and after schemas, followed by an empty diff

Actual behaviour:

• The output stops before the first schema is printed, and the rest is lost.