Date header breaks AttemptClockSkewHandler

[mrsufgi]

Confirm by changing [ ] to [x] below to ensure that it's a bug:

• I've gone through the API reference
• I've checked AWS Forums and StackOverflow for answers
• I've searched for previous similar issues and didn't find any solution

Describe the bug
Noticed error logs since May 1st, checked and it didn't happen before.
Error logs:

2020/05/04 08:48:10 ERROR: unable to determine clock skew for Kinesis/PutRecord API response, invalid Date header value, Mon, 4 May 2020 08:48:10 GMT.

As you can tell the date header is Mon, 4 May 2020 which is an invalid date, missing 0 before the 4.

What is the origin of the Date header? might it be a user error? Am I doing something wrong?

func (p *kinesisProducerRepository) Publish(b []byte) error {
	randomPartitionKey := utils.RandomString(PartitionKeyLength)
	input := &kinesis.PutRecordInput{
		Data:         b,
		StreamName:   p.streamName,
		PartitionKey: &randomPartitionKey,
	}

	req := p.kc.PutRecordRequest(input)
	resp, err := req.Send(context.TODO())
	return err
}

Version of AWS SDK for Go?
v0.20.0

Version of Go (go version)?
1.14

To Reproduce (observed behavior)
https://play.golang.org/p/iWcVnT9MEhs

Expected behavior
No errors between 1-9 day of the month

[jasdel]

Thanks for reporting this bug @mrsufgi. Looks like the SDK's usage of the standard library default Date parsing isn't sufficient. It looks like PR #560 adds a fix for this behavior to allow the SDK to work more correctly with the additional format. We're review that PR and look for a fix from there.