Add publicly accessible units to constants.py

https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/API_MetricDatum.html

Author: jen-w

aws_embedded_metrics/constants.py

@@ -14,3 +14,31 @@
 DEFAULT_NAMESPACE = "aws-embedded-metrics"
 MAX_DIMENSIONS = 9
 MAX_METRICS_PER_EVENT = 100
+
+# Units
+SECONDS = "Seconds"
+MICROSECONDS = "Microseconds"
+MILLISECONDS = "Milliseconds"
+BYTES = "Bytes"
+KILOBYTES = "Kilobytes"
+MEGABYTES = "Megabytes"
+GIGABYTES = "Gigabytes"
+TERABYTES = "Terabytes"
+BITS = "Bits"
+KILOBITS = "Kilobits"
+MEGABITS = "Megabits"
+GIGABITS = "Gigabits"
+TERABITS = "Terabits"
+PERCENT = "Percent"
+COUNT = "Count"
+BYTES_PER_SECOND = "Bytes/Second"
+KILOBYTES_PER_SECOND = "Kilobytes/Second"
+MEGABYTES_PER_SECOND = "Megabytes/Second"
+GIGABYTES_PER_SECOND = "Gigabytes/Second"
+TERABYTES_PER_SECOND = "Terabytes/Second"
+BITS_PER_SECOND = "Bits/Second"
+KILOBITS_PER_SECOND = "Kilobits/Second"
+MEGABITS_PER_SECOND = "Megabits/Second"
+GIGABITS_PER_SECOND = "Gigabits/Second"
+TERABITS_PER_SECOND = "Terabits/Second"
+COUNT_PER_SECOND = "Count/Second"