Set this.isCancelled in close method of streamSink.

[mukulmishra18]

Fixes #8816 . This PR tries to fix the intermittent error Error: close should have stream controller thrown raised during unit tests.

I cannot see where we are setting sink.isCancelled = true, when close() method of streamSink is called. So, I think adding this.isCancelled = true; in close() method itself, may fix this intermittent error.

@timvandermeij can you please check if this fixes the problem, as I cannot reproduce this error locally.

[Snuffleupagus]

/botio unittest

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Live output at: http://54.215.176.217:8877/deef3b564502e27/output.txt

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From: Bot.io (Linux m4)

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Success

Full output at http://54.67.70.0:8877/e49fe04a88372a2/output.txt

Total script time: 2.53 mins

• Unit Tests: Passed

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From: Bot.io (Windows)

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Success

Full output at http://54.215.176.217:8877/deef3b564502e27/output.txt

Total script time: 12.50 mins

• Unit Tests: Passed

[timvandermeij]

/botio unittest

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Command cmd_unittest from @timvandermeij received. Current queue size: 1

Live output at: http://54.67.70.0:8877/4fbb708eccff45f/output.txt

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From: Bot.io (Linux m4)

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Success

Full output at http://54.67.70.0:8877/4fbb708eccff45f/output.txt

Total script time: 2.54 mins

• Unit Tests: Passed

[pdfjsbot]

From: Bot.io (Windows)

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Success

Full output at http://54.215.176.217:8877/1055e97a251dfcc/output.txt

Total script time: 12.74 mins

• Unit Tests: Passed

[timvandermeij]

/botio test

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Command cmd_test from @timvandermeij received. Current queue size: 0

Live output at: http://54.215.176.217:8877/b53564c8667caaa/output.txt

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From: Bot.io (Linux m4)

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Success

Full output at http://54.67.70.0:8877/6c1c03396d4cf11/output.txt

Total script time: 16.51 mins

• Font tests: Passed
• Unit tests: Passed
• Regression tests: Passed

[pdfjsbot]

From: Bot.io (Windows)

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Success

Full output at http://54.215.176.217:8877/b53564c8667caaa/output.txt

Total script time: 29.68 mins

• Font tests: Passed
• Unit tests: Passed
• Regression tests: Passed

[timvandermeij]

Looks good. Thank you!