Can't instantiate abstract class SfpUtil with abstract methods get_transceiver_change_event

[lguohan]

Description

Steps to reproduce the issue:
1.
2.
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Describe the results you received:

https://groups.google.com/forum/#!topic/sonicproject/7YeMVQRbbLs

Describe the results you expected:

Additional information you deem important (e.g. issue happens only occasionally):

**Output of `show version`:**

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**Attach debug file `sudo generate_dump`:**

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[jleveque]

All plugins which inherit the base class must define a concrete implementation of every abstract property and method, otherwise this error will be encountered. When adding a new abstract property or method to a base class, one should also add concrete implementations to all subclasses in the project. The concrete methods can simply be stubs with a "TODO" comment and a raise NotImplementedError instruction.

[keboliu]

as Joe mentioned, in the implementation of xcvrd, some more method was added, all the platforms need to implement this method or add a stub.

[lguohan]

@keboliu, please add a stub for all other platforms which do not have implementation yet. The reason is that we cannot break other platforms when introducing new functions.

[xinliu-seattle]

@keboliu, can you input the repro steps, I will ping all platform vendors to add this support.

[keboliu]

@xinliu-seattle for the way to reproduce this issue, please check this link https://groups.google.com/forum/#!topic/sonicproject/7YeMVQRbbLs.
@lguohan I'd like to resolve this issue and have Xcvrd work on all the platforms, but I have concern to modify the code on other platforms directly, it's not about efforts, it's about capability and ownership.

[lguohan]

@keboliu, it won't work if we break other platforms when we introduce new APIs. The right thing to do is to first add dummy interface all platform as suggested by Joe. Then, later those platforms can implemented their own.

[keboliu]

@lguohan @xinliu-seattle I can create PR to add stubs to other platforms, but without verification as you know I don't have other platforms. Do we have some list for the platform should be included or just all the platforms?

[lguohan]

all platforms with sfputil.py plugin in their folder.

[lguohan]

we cannot ask you to do the test, but the syntax of the code should be correct.

[keboliu]

please check PR #2038

[lguohan]

thanks!