[tizen_rpc_port] Resolved issue with failure to receive events in multiple proxies.

[upple]

Fixes:

• Resolved issue with failure to receive events in multiple proxies.

[JSUYA]

Sorry for the late review. Please check the comments.

I'm not sure of the exact reason, when I run the server example, the following exception occurs.
It seems the tizen/rpc_port_stub channel doesn't have a handle when it connects.
Is there a setting I need to check?
(The device is a Tizen 9.0 TV.)

══╡ EXCEPTION CAUGHT BY SERVICES LIBRARY ╞══════════════════════════════════════════════════════════
The following PlatformException was thrown while activating platform stream on channel
tizen/rpc_port_stub:
PlatformException(Invalid arguments, No handle provided., null, null)

When the exception was thrown, this was the stack:
#0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:652:7)
#1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:370:18)
<asynchronous suspension>
#2      EventChannel.receiveBroadcastStream.<anonymous closure> (package:flutter/src/services/platform_channel.dart:715:11)
<asynchronous suspension>
════════════════════════════════════════════════════════════════════════════════════════════════════

[upple]

No handle provided.

Hello. @JSUYA
When I test this from rpi4, It works fine.
I can't find the issue.
Does this occur only on tv target?

[upple]

Thank you for your review.
I applied your feedbacks.
Please check my reply.

[JSUYA]

I confirmed that even on the same 32-bit architecture device, the TV(tizen 9.0) cannot convert the handle to int64_t.
I will apply a separate patch for this.