More precise timestamps by using nanos offsets where available

[codefromthecrypt]

This change brings Brave into the best timestamp practice by doing the
following:

• Fixes unsafe access to Span.startTick
• Records Span.startTick when starting any span the local process owns
• Ensures Span.timestamp/duration are not reported on spans the local process doesn't own
• Uses nanos offsets where available for annotation timestamps

The above corrects the common misalignment of spans in the UI, where
within a local process, operations that vary on microsecond basis have
annotations that extend beyond the span duration.

See openzipkin/openzipkin.github.io#49

[codefromthecrypt]

Here's a beautifully aligned microsecond precision trace, made with the pending okhttp interceptor.

[
  {
    "traceId": "e73635b3e7c1df4d",
    "id": "e73635b3e7c1df4d",
    "name": "get",
    "timestamp": 1474992370922000,
    "duration": 158169,
    "annotations": [
      {
        "timestamp": 1474992370922000,
        "value": "sr",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      },
      {
        "timestamp": 1474992371080169,
        "value": "ss",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      }
    ],
    "binaryAnnotations": [
      {
        "key": "http.status_code",
        "value": "200",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      },
      {
        "key": "http.url",
        "value": "/api/v1/traces",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      }
    ]
  },
  {
    "traceId": "e73635b3e7c1df4d",
    "id": "2c2c48ed6dc4fb91",
    "name": "get-traces",
    "parentId": "e73635b3e7c1df4d",
    "timestamp": 1474992370948000,
    "duration": 121927,
    "binaryAnnotations": [
      {
        "key": "lc",
        "value": "ElasticsearchStorage",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      },
      {
        "key": "request",
        "value": "QueryRequest{serviceName=elasticsearch, spanName=null, annotations=[], binaryAnnotations={}, minDuration=null, maxDuration=null, endTs=1474992245496, lookback=3600000, limit=10}",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      }
    ]
  },
  {
    "traceId": "e73635b3e7c1df4d",
    "id": "72250d0541592509",
    "name": "search-spansaggregations",
    "parentId": "e73635b3e7c1df4d",
    "timestamp": 1474992371030000,
    "duration": 14945,
    "binaryAnnotations": [
      {
        "key": "lc",
        "value": "okhttp",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      }
    ]
  },
  {
    "traceId": "e73635b3e7c1df4d",
    "id": "a5482d613b612827",
    "name": "search-spans",
    "parentId": "e73635b3e7c1df4d",
    "timestamp": 1474992371048000,
    "duration": 7794,
    "binaryAnnotations": [
      {
        "key": "lc",
        "value": "okhttp",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      }
    ]
  },
  {
    "traceId": "e73635b3e7c1df4d",
    "id": "8db9d7bf1213856a",
    "name": "post",
    "parentId": "72250d0541592509",
    "timestamp": 1474992371035000,
    "duration": 9795,
    "annotations": [
      {
        "timestamp": 1474992371035000,
        "value": "cs",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      },
      {
        "timestamp": 1474992371044795,
        "value": "cr",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      }
    ],
    "binaryAnnotations": [
      {
        "key": "http.url",
        "value": "http://localhost:9200/zipkin-2016-09-27/span/_search?ignore_unavailable=true&allow_no_indices=true&expand_wildcards=open",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      },
      {
        "key": "sa",
        "value": true,
        "endpoint": {
          "serviceName": "elasticsearch",
          "ipv4": "127.0.0.1",
          "port": 9200
        }
      }
    ]
  },
  {
    "traceId": "e73635b3e7c1df4d",
    "id": "4c3537b7a695a8cc",
    "name": "post",
    "parentId": "a5482d613b612827",
    "timestamp": 1474992371050000,
    "duration": 5904,
    "annotations": [
      {
        "timestamp": 1474992371050000,
        "value": "cs",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      },
      {
        "timestamp": 1474992371055904,
        "value": "cr",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      }
    ],
    "binaryAnnotations": [
      {
        "key": "http.url",
        "value": "http://localhost:9200/zipkin-2016-09-27/span/_search?ignore_unavailable=true&allow_no_indices=true&expand_wildcards=open",
        "endpoint": {
          "serviceName": "zipkin-server",
          "ipv4": "192.168.99.1",
          "port": 9411
        }
      },
      {
        "key": "sa",
        "value": true,
        "endpoint": {
          "serviceName": "elasticsearch",
          "ipv4": "127.0.0.1",
          "port": 9200
        }
      }
    ]
  }
]

[schlosna]

Should this be synchronizing on the span rather than this?

[codefromthecrypt]

another good catch. thanks!