src: store onread callback in internal field

This gives a slight performance improvement. At 2000 runs:

                                            confidence improvement accuracy (*)   (**)  (***)
    net/net-c2s.js dur=5 type='buf' len=64        ***      0.54 %       ±0.16% ±0.21% ±0.27%

PR-URL: https://github.com/nodejs/node/pull/26837
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

1 files changed, 0 insertions, 1 deletions

diff --git a/src/env.h b/src/env.h
index dfe9af01ae..fcd36f5a92 100644
--- a/src/env.h
+++ b/src/env.h
@@ -241,7 +241,6 @@ constexpr size_t kFsStatsBufferLength = kFsStatsFieldsNumber * 2;
   V(onmessage_string, "onmessage")                                             \
   V(onnewsession_string, "onnewsession")                                       \
   V(onocspresponse_string, "onocspresponse")                                   \
-  V(onread_string, "onread")                                                   \
   V(onreadstart_string, "onreadstart")                                         \
   V(onreadstop_string, "onreadstop")                                           \
   V(onshutdown_string, "onshutdown")                                           \