Set bucket boundaries for histogram metrics (#14)

Set appropriate bucket boundaries for histogram metrics to accommodate
the distribution of measured values.

Author: masih

sender/metrics.go

@@ -24,11 +24,13 @@ var (
 		sendLatency: must(meter.Float64Histogram(
 			"send_latency",
 			metric.WithDescription("Latency of sending transactions in seconds"),
-			metric.WithUnit("s"))),
+			metric.WithUnit("s"),
+			metric.WithExplicitBucketBoundaries(0.1, 0.2, 0.3, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0, 20.0))),
 		receiptLatency: must(meter.Float64Histogram(
 			"receipt_latency",
 			metric.WithDescription("Latency of sending transactions in seconds"),
-			metric.WithUnit("s"))),
+			metric.WithUnit("s"),
+			metric.WithExplicitBucketBoundaries(0.1, 0.2, 0.3, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0, 20.0))),
 		workerQueueLength: must(meter.Int64ObservableGauge(
 			"worker_queue_length",
 			metric.WithDescription("Length of the worker's queue"),

stats/metrics.go

@@ -16,15 +16,17 @@ var (
 		gasUsed: must(meter.Int64Histogram(
 			"gas_used",
 			metric.WithDescription("Gas used in transactions"),
-			metric.WithUnit("{gas}"))),
+			metric.WithUnit("{gas}"),
+			metric.WithExplicitBucketBoundaries(1, 1000, 10_000, 50_000, 100_000, 200_000, 300_000, 400_000, 500_000, 600_000, 700_000, 800_000, 1_000_000))),
 		blockNumber: must(meter.Int64Gauge(
 			"block_number",
 			metric.WithDescription("Block number in the chain"),
 			metric.WithUnit("{height}"))),
 		blockTime: must(meter.Float64Histogram(
 			"block_time",
 			metric.WithDescription("Time taken to produce a block"),
-			metric.WithUnit("s"))),
+			metric.WithUnit("s"),
+			metric.WithExplicitBucketBoundaries(0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 5.0, 10.0, 20.0))),
 	}
 )