make calculateDistance run on mainThread

[zyxkad]

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• Please check if the PR fulfills these requirements

• The commit message are well described
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• What kind of change does this PR introduce? (Bug fix, feature, ...)
  Bug fix

• What is the current behavior? (You can also link to an open issue here)
  Calculate distance method is not run on the main thread which cause possible thread sync issue

• What is the new behavior (if this is a feature change)?

• Does this PR introduce a breaking change? (What changes might users need to make in their scripts due to this PR?)

• Other information:

[SirEndii]

Checkstyle seems to have some warnings
Not sure if they came from our other PR
But could you fix them?