Native: use IPC instead of flushing to disk where possible

[jpnurmi]

Proposal: use IPC instead of flushing to disk to speed up scope changes, such as setting tags. For example, send messages over a named pipe on Windows.

As a rough comparison, with Crashpad (Windows Defender and external crash reports disabled):

• flush scope to disk (set tag): ~0.5ms
• send IPC message (add attachment): ~0.1ms

Based on that, we could estimate that switching the native backend from disk flushes to IPC messages could result in a ~5x speedup when setting tags on Windows.

See also:

• sentry_set_context opens file handles resulting in hitches #1395

[linear-code]

NATIVE-196

[jpnurmi]

Even though sentry__scope_apply_to_event is a relatively small part of the whole scope flush process, it's also worth noting that #1794 optimizes that part quite a bit:

• perf: copy-on-write for sentry_value_t clone #1794