[ISSUE #933] fix retry topic and namespace topic block

[0daypwn]

What is the purpose of the change

close #933

Brief changelog

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Verifying this change

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[0daypwn]

map is not thread safe, so should add RWMutex.
The design is too complicated. Maybe there's a better way?

[ShannonDing]

@0daypwn , hi, it seems have conflicts after PR #944 merged, could you pls fix it and and have a test after the crCh initialized?

[0daypwn]

The purpose of these two is the same.

but the pc.crCh Map may be read and written concurrently in two places

• Subscribe
• consumeMessageCurrently
  it may cause panic.

@ShannonDing @NeonToo

[maixiaohai]

@0daypwn pls resolve the conflicts first