How to use the @opencensus/core.globalStats.createMeasureDouble function in @opencensus/core

const app = express();
app.use(express.static("web_client"));
app.use(bodyParser.json());

// The project id must be provided for running in a local environment
const project = process.env.GOOGLE_CLOUD_PROJECT;
assert(typeof project !== 'undefined' && project,
  "Please set environment variable GOOGLE_CLOUD_PROJECT to the project id.");
console.log(`Sending metrics data to project: ${project}`);

// OpenCensus setup
// [START web_client_monitoring_ocsetup]
const exporter = new StackdriverStatsExporter({projectId: project});
globalStats.registerExporter(exporter);
const mLatencyMs = globalStats.createMeasureDouble("webmetrics/latency",
                       MeasureUnit.MS,
                       "Latency related to page loading");
const mClickCount = globalStats.createMeasureInt64("webmetrics/click_count",
                       MeasureUnit.UNIT,
                       "Number of clicks");
const buckets = [0, 1, 2, 3, 4, 5, 6, 8, 10, 13, 16, 20, 25, 30, 40, 50, 65, 80,
                100, 130, 160, 200, 250, 300, 400, 500, 650, 800, 1000, 2000,
                5000, 10000, 20000, 50000, 100000];

const tagPhase = { name: "phase" };
const tagClient = { name: "client" };

const latencyView = globalStats.createView(
  "webmetrics/latency",
  mLatencyMs,
  AggregationType.DISTRIBUTION,

const readline = require('readline');

// [START setup_exporter]
// Enable OpenCensus exporters to export metrics to Prometheus Monitoring.
const exporter = new PrometheusStatsExporter({
  // Metrics will be exported on https://localhost:{port}/metrics
  port: 9464,
  startServer: true
});

// Pass the created exporter to global Stats
globalStats.registerExporter(exporter);
// [END setup_exporter]

// The latency in milliseconds
const mLatencyMs = globalStats.createMeasureDouble(
  'repl/latency',
  MeasureUnit.MS,
  'The latency in milliseconds per REPL loop'
);

// Counts/groups the lengths of lines read in.
const mLineLengths = globalStats.createMeasureInt64(
  'repl/line_lengths',
  MeasureUnit.BYTE,
  'The distribution of line lengths'
);

// Create a stream to read our file
const stream = fs.createReadStream('./test.txt');

// Create an interface to read and process our file line by line

// A Stackdriver workspace is required and provided through the environment as ${GOOGLE_PROJECT_ID}
const projectId = process.env.GOOGLE_PROJECT_ID;

// GOOGLE_APPLICATION_CREDENTIALS are expected by a dependency of this code
// Not this code itself. Checking for existence here but not retaining (as not needed)
if (!projectId || !process.env.GOOGLE_APPLICATION_CREDENTIALS) {
  throw Error('Unable to proceed without a Project ID');
}
const exporter = new StackdriverStatsExporter({ projectId: projectId });

// Pass the created exporter to global Stats
globalStats.registerExporter(exporter);
// [END setup_exporter]

// The latency in milliseconds
const mLatencyMs = globalStats.createMeasureDouble(
  'repl/latency',
  MeasureUnit.MS,
  'The latency in milliseconds per REPL loop'
);

// Counts/groups the lengths of lines read in.
const mLineLengths = globalStats.createMeasureInt64(
  'repl/line_lengths',
  MeasureUnit.BYTE,
  'The distribution of line lengths'
);

// Create a stream to read our file
const stream = fs.createReadStream('./test.txt');

// Create an interface to read and process our file line by line

*
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

const {globalStats, MeasureUnit, TagMap} = require('@opencensus/core');

const K1 = { name: 'k1' };
const K2 = { name: 'k2' };
const V1 = { value: 'v1' };
const V2 = { value: 'v2' };

const mLatencyMs = globalStats.createMeasureDouble(
  'm1', MeasureUnit.MS, '1st test metric'
);

/** Main method. */
function main () {
  const tags1 = new TagMap();
  tags1.set(K1, V1);

  globalStats.withTagContext(tags1, () => {
    console.log('Enter Scope 1');
    printMap('Add Tags', tags1.tags);
    printMap('Current Tags == Default + tags1:',
    globalStats.getCurrentTagContext().tags);

    const tags2 = new TagMap();
    tags2.set(K2, V2);

*/
export const GRPC_CLIENT_RECEIVED_BYTES_PER_RPC: Measure = globalStats.createMeasureInt64(
  'grpc.io/client/received_bytes_per_rpc',
  MeasureUnit.BYTE,
  'Total bytes received across all response messages per RPC.'
);

/** {@link Measure} for gRPC client roundtrip latency in milliseconds. */
export const GRPC_CLIENT_ROUNDTRIP_LATENCY: Measure = globalStats.createMeasureDouble(
  'grpc.io/client/roundtrip_latency',
  MeasureUnit.MS,
  'Time between first byte of request sent to last byte of response received, or terminal error.'
);

/** {@link Measure} for gRPC server latency in milliseconds. */
export const GRPC_CLIENT_SERVER_LATENCY: Measure = globalStats.createMeasureDouble(
  'grpc.io/client/server_latency',
  MeasureUnit.MS,
  'Propagated from the server and should have the same value as "grpc.io/server/latency'
);

/**
 * Tag key that represents a client gRPC method.
 *
 * {@link #GRPC_CLIENT_METHOD} is set when an outgoing request starts and is
 * available in all the recorded metrics.
 */
export const GRPC_CLIENT_METHOD = {
  name: 'grpc_client_method',
};

/**

'grpc.io/client/received_messages_per_rpc',
  MeasureUnit.UNIT,
  'Number of response messages received per RPC (always 1 for non-streaming RPCs).'
);

/**
 * {@link Measure} for total bytes received across all response messages per RPC
 */
export const GRPC_CLIENT_RECEIVED_BYTES_PER_RPC: Measure = globalStats.createMeasureInt64(
  'grpc.io/client/received_bytes_per_rpc',
  MeasureUnit.BYTE,
  'Total bytes received across all response messages per RPC.'
);

/** {@link Measure} for gRPC client roundtrip latency in milliseconds. */
export const GRPC_CLIENT_ROUNDTRIP_LATENCY: Measure = globalStats.createMeasureDouble(
  'grpc.io/client/roundtrip_latency',
  MeasureUnit.MS,
  'Time between first byte of request sent to last byte of response received, or terminal error.'
);

/** {@link Measure} for gRPC server latency in milliseconds. */
export const GRPC_CLIENT_SERVER_LATENCY: Measure = globalStats.createMeasureDouble(
  'grpc.io/client/server_latency',
  MeasureUnit.MS,
  'Propagated from the server and should have the same value as "grpc.io/server/latency'
);

/**
 * Tag key that represents a client gRPC method.
 *
 * {@link #GRPC_CLIENT_METHOD} is set when an outgoing request starts and is

/** {@link Measure} for gRPC server latency in milliseconds. */
export const GRPC_SERVER_SERVER_LATENCY: Measure = globalStats.createMeasureDouble(
  'grpc.io/server/server_latency',
  MeasureUnit.MS,
  'Time between first byte of request received to last byte of response sent, or terminal error.'
);

/** {@link Measure} for number of messages sent in each RPC. */
export const GRPC_SERVER_SENT_MESSAGES_PER_RPC: Measure = globalStats.createMeasureInt64(
  'grpc.io/server/sent_messages_per_rpc',
  MeasureUnit.UNIT,
  'Number of messages sent in each RPC. Has value 1 for non-streaming RPCs.'
);

/** {@link Measure} for total bytes received across all messages per RPC. */
export const GRPC_SERVER_RECEIVED_BYTES_PER_RPC: Measure = globalStats.createMeasureDouble(
  'grpc.io/server/received_bytes_per_rpc',
  MeasureUnit.BYTE,
  'Total bytes received across all messages per RPC.'
);

/**
 * {@link Measure} for total bytes sent across all response messages per RPC.
 */
export const GRPC_SERVER_SENT_BYTES_PER_RPC: Measure = globalStats.createMeasureDouble(
  'grpc.io/server/sent_bytes_per_rpc',
  MeasureUnit.BYTE,
  'Total bytes sent in across all response messages per RPC'
);

/**
 * Tag key that represents a server gRPC method.

* bodies (not including headers but including error responses with bodies).
 * Should be measured from actual bytes received and read, not the value of
 * the Content-Length header. This is uncompressed bytes. Responses with no
 * body should record 0 for this value.
 */
export const HTTP_CLIENT_RECEIVED_BYTES: Measure = globalStats.createMeasureInt64(
  'opencensus.io/http/client/received_bytes',
  MeasureUnit.BYTE,
  'Client-side total bytes received in response bodies (uncompressed)'
);

/**
 * {@link Measure} for the client-side time between first byte of request
 * headers sent to last byte of response received, or terminal error.
 */
export const HTTP_CLIENT_ROUNDTRIP_LATENCY: Measure = globalStats.createMeasureDouble(
  'opencensus.io/http/client/roundtrip_latency',
  MeasureUnit.MS,
  'Client-side time between first byte of request headers sent to last byte of response received, or terminal error'
);

/**
 * {@link Measure} for the server-side total bytes received in request body
 * (not including headers). This is uncompressed bytes.
 */
export const HTTP_SERVER_RECEIVED_BYTES: Measure = globalStats.createMeasureInt64(
  'opencensus.io/http/server/received_bytes',
  MeasureUnit.BYTE,
  'Server-side total bytes received in request body (uncompressed)'
);

/**

'grpc.io/server/sent_messages_per_rpc',
  MeasureUnit.UNIT,
  'Number of messages sent in each RPC. Has value 1 for non-streaming RPCs.'
);

/** {@link Measure} for total bytes received across all messages per RPC. */
export const GRPC_SERVER_RECEIVED_BYTES_PER_RPC: Measure = globalStats.createMeasureDouble(
  'grpc.io/server/received_bytes_per_rpc',
  MeasureUnit.BYTE,
  'Total bytes received across all messages per RPC.'
);

/**
 * {@link Measure} for total bytes sent across all response messages per RPC.
 */
export const GRPC_SERVER_SENT_BYTES_PER_RPC: Measure = globalStats.createMeasureDouble(
  'grpc.io/server/sent_bytes_per_rpc',
  MeasureUnit.BYTE,
  'Total bytes sent in across all response messages per RPC'
);

/**
 * Tag key that represents a server gRPC method.
 *
 * {@link #GRPC_SERVER_METHOD} is set when an incoming request starts and is
 * available in the context for the entire RPC call handling.
 */
export const GRPC_SERVER_METHOD = {
  name: 'grpc_server_method',
};

/**

import {
  DEFAULT_BYTES_DISTRIBUTION,
  DEFAULT_MESSAGE_COUNT_DISTRIBUTION,
  DEFAULT_MILLI_SECONDS_DISTRIBUTION,
} from './common-distributions';

/** {@link Measure} for number of messages received in each RPC. */
export const GRPC_SERVER_RECEIVED_MESSAGES_PER_RPC: Measure = globalStats.createMeasureInt64(
  'grpc.io/server/received_messages_per_rpc',
  MeasureUnit.UNIT,
  'Number of messages received in each RPC. Has value 1 for non-streaming RPCs.'
);

/** {@link Measure} for gRPC server latency in milliseconds. */
export const GRPC_SERVER_SERVER_LATENCY: Measure = globalStats.createMeasureDouble(
  'grpc.io/server/server_latency',
  MeasureUnit.MS,
  'Time between first byte of request received to last byte of response sent, or terminal error.'
);

/** {@link Measure} for number of messages sent in each RPC. */
export const GRPC_SERVER_SENT_MESSAGES_PER_RPC: Measure = globalStats.createMeasureInt64(
  'grpc.io/server/sent_messages_per_rpc',
  MeasureUnit.UNIT,
  'Number of messages sent in each RPC. Has value 1 for non-streaming RPCs.'
);

/** {@link Measure} for total bytes received across all messages per RPC. */
export const GRPC_SERVER_RECEIVED_BYTES_PER_RPC: Measure = globalStats.createMeasureDouble(
  'grpc.io/server/received_bytes_per_rpc',
  MeasureUnit.BYTE,