[Bug]: signalingClientSendMessageSync delay

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Describe the bug

We are using the sdk in master mode with no problems with Trickle ICE enabled clients.

Working with Alexa (that does not support Trickle ICE) we discovered a random delay (from 0 to 10 seconds) waiting for the reply of function signalingClientSendMessageSync.

After some investigations we noted that this delay is produced by this code:

amazon-kinesis-video-streams-webrtc-sdk-c/src/source/Signaling/LwsApiCalls.c

Line 1929 in 74e7f68

    
           CHK_STATUS(CVAR_WAIT(pSignalingClient->sendCvar, pSignalingClient->sendLock, SIGNALING_SEND_TIMEOUT));

Playing around the defined constants we found that lowering the constant SIGNALING_SERVICE_WSS_PING_PONG_INTERVAL_IN_SECONDS from 10 to 3 seconds, we experiment that the random delay never exceeds 3 seconds.

Expected Behavior

We expect that message is sent as soon as the function signalingClientSendMessageSync has been raised.

Current Behavior

The message is not sent immediatly but with a random delay between 0 and 10 seconds.

Reproduction Steps

For some reason this issue is not relevant when Trickle ICE is enabled. We have discovered this issue working with Alexa because Trickle ICE is not supported and the required 6 seconds timeout if often unsatisfied.

WebRTC C SDK version being used

branch release-1.10.0

Compiler and Version used

gcc (GCC) 12.3.0

Operating System and version

Linux 6.1.54-v7l

Platform being used

Raspberry CM4

Working on the issue we found that wakeLwsServiceEventLoop is called before the wait of the reply.

amazon-kinesis-video-streams-webrtc-sdk-c/src/source/Signaling/LwsApiCalls.c

Line 1918 in 74e7f68

CHK_STATUS(wakeLwsServiceEventLoop(pSignalingClient, PROTOCOL_INDEX_WSS));

The problem is that the lwsHttpCallbackRoutine is not called immediatly but only at the next pong.

amazon-kinesis-video-streams-webrtc-sdk-c/src/source/Signaling/LwsApiCalls.h

Line 21 in 74e7f68

#define SIGNALING_SERVICE_WSS_PING_PONG_INTERVAL_IN_SECONDS 10

Can we add more information?

My fault, i used lws from meta-openembedded and it use libuv as a default. Removing libuv solve the issue.

Closing assuming resolved. Feel free to reopen / open a new issue if problem persists