searchidxshard: drop unused `echo' sub

We no longer need a separate `echo' command to check the
doneness of a previous ->ipc_do command since we've made
->ipc_do async and introduced ->ipc_wait_all in commit
f0b9f90a (*index: propagate exceptions from shard processes, 2025-09-04)

diff --git a/lib/PublicInbox/SearchIdxShard.pm b/lib/PublicInbox/SearchIdxShard.pm
index 8de79b78229d2a978f1cf9b6eca4301c928d93d6..3b8402b7ebcda13d4ddc59cd01d16d136b736654 100644 (file)
--- a/lib/PublicInbox/SearchIdxShard.pm
+++ b/lib/PublicInbox/SearchIdxShard.pm
@@ -58,12 +58,6 @@ sub add_eidx_info {
        $self->ipc_do('add_eidx_info_raw', $docid, $eidx_key, @list_ids);
 }
 
-# wait for return to determine when ipc_do('commit_txn_lazy') is done
-sub echo {
-       shift;
-       "@_";
-}
-
 sub idx_close {
        my ($self) = @_;
        die "BUG: $$ $0 txn active" if $self->{txn};