CloudWatch GetMetricData() returns "MalformedInput: timestamp must follow ISO8601"

[ellagxy]

Please fill out the sections below to help us address your issue.

Version of AWS SDK for Go?

1.34.10

Version of Go (go version)?

go version go1.14.7 linux/amd64

What issue did you see?

When call GetMetricData(), it returns "MalformedInput: timestamp must follow ISO8601" error.

Steps to reproduce

1. My code to form GetMetricDataInput with timestamp:
   endTime := time.Now()
   duration, _ := time.ParseDuration("-60s")
   startTime := endTime.Add(duration)
   getMetricDataInput := &cloudwatch.GetMetricDataInput{
   StartTime: aws.Time(startTime),
   EndTime: aws.Time(endTime),
   MetricDataQueries: metricDataQueries,
   }

2. Same timestamp code I did not see issue with AWS SDK 1.34.7

3. I was printing out my GetMetricDataInput and timestamp looks like below:
   StartTime: 2020-08-26 17:27:42.921042773 +0000 UTC m=-174.480789205,
   EndTime: 2020-08-26 17:28:42.921042773 +0000 UTC m=-114.480789205,

4. I thought it might be related to the time on my computer where I did GetMetricData() call, so I moved endTime and startTime 5min before then time.Now() but still seeing same issue.

If you have an runnable example, please include it.

[skmcgrail]

Thanks for the report @ellagxy, this issue is being tracked in #3498. Closing this issue since it is a duplicate.