fix: only send metrics if there is data to send. (#58)

[rarruda]

We want to preserve the backend from having to work, when there is no work to be done.

[coveralls]

Pull Request Test Coverage Report for Build 1589092239

• 59 of 62 (95.16%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+5.8%) to 96.181%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
spec/unleash/metrics_reporter_spec.rb	45	46	97.83%
lib/unleash/client.rb	0	2	0.0%

Totals
Change from base Build 1577747545:	5.8%
Covered Lines:	1486
Relevant Lines:	1545

---

💛 - Coveralls

[github-actions]

[rubocop] <Lint/AmbiguousBlockAssociation> _{reported by reviewdog 🐶}
Parenthesize the param `have_requested(:post, 'http://test-url/client/metrics')
.with(
body: hash_including(
appName: "my-test-app",
instanceId: "rspec/test"
)
)
.with { |req|
hash = JSON.parse(req.body)

    [
      DateTime.parse(hash['bucket']['stop']) >= DateTime.parse(hash['bucket']['start']),
      hash['bucket']['toggles']['featureA']['yes'] == 3,
      hash['bucket']['toggles']['featureA']['no'] == 2,
      hash['bucket']['toggles']['featureB']['yes'] == 1
    ].all?(true)
  }` to make sure that the block will be associated with the `have_requested(:post, 'http://test-url/client/metrics')
  .with(
    body: hash_including(
      appName: "my-test-app",
      instanceId: "rspec/test"
    )
  )
  .with` method call.

[github-actions]

[rubocop] <Lint/AmbiguousBlockAssociation> _{reported by reviewdog 🐶}
Parenthesize the param `have_requested(:post, 'http://test-url/client/metrics')
.with(
body: hash_including(
appName: "my-test-app",
instanceId: "rspec/test"
)
)
.with { |req|
hash = JSON.parse(req.body)

    [
      DateTime.parse(hash['bucket']['stop']) >= DateTime.parse(hash['bucket']['start']),
      hash['bucket']['toggles']['featureA']['yes'] == 3,
      hash['bucket']['toggles']['featureA']['no'] == 2,
      hash['bucket']['toggles']['featureB']['yes'] == 1
    ].all?(true)
  }` to make sure that the block will be associated with the `have_requested(:post, 'http://test-url/client/metrics')
  .with(
    body: hash_including(
      appName: "my-test-app",
      instanceId: "rspec/test"
    )
  )
  .with` method call.

[sonatype-lift]

Lint/AmbiguousBlockAssociation: Parenthesize the param `have_requested(:post, 'http://test-url/client/metrics')
.with(
body: hash_including(
appName: "my-test-app",
instanceId: "rspec/test"
)
)
.with { |req|
hash = JSON.parse(req.body)

    [
      DateTime.parse(hash['bucket']['stop']) >= DateTime.parse(hash['bucket']['start']),
      hash['bucket']['toggles']['featureA']['yes'] == 3,
      hash['bucket']['toggles']['featureA']['no'] == 2,
      hash['bucket']['toggles']['featureB']['yes'] == 1
    ].all?(true)
  }` to make sure that the block will be associated with the `have_requested(:post, 'http://test-url/client/metrics')
  .with(
    body: hash_including(
      appName: "my-test-app",
      instanceId: "rspec/test"
    )
  )
  .with` method call.

(at-me in a reply with help or ignore)

[sighphyre]

Looks good