Add `Keyring.verify_events_for_server` and reduce memory usage (#10018)

Also add support for giving a callback to generate the JSON object to
verify. This should reduce memory usage, as we no longer have the event
in memory in dict form (which has a large memory footprint) for extend
periods of time.

1 files changed, 1 insertions, 0 deletions

diff --git a/changelog.d/10018.misc b/changelog.d/10018.misc
new file mode 100644
index 0000000000..eaf9f64867
--- /dev/null
+++ b/changelog.d/10018.misc
@@ -0,0 +1 @@
+Reduce memory usage when verifying signatures on large numbers of events at once.