},
	{
		api:     "metrics",
		methods: []string{http.MethodGet, http.MethodPut, http.MethodDelete},
		queries: []string{"metrics", ""},
	},
	{
		api:     "website",
		methods: []string{http.MethodPut},
		queries: []string{"website", ""},
	},
	{
		api:     "logging",
		methods: []string{http.MethodPut, http.MethodDelete},
		queries: []string{"logging", ""},
	},
	{
		api:     "accelerate",

	"response-content-type",
	"response-expires",
	"retention",
	"select",
	"select-type",
	"tagging",
	"torrent",
	"uploadId",
	"uploads",
	"versionId",
	"versioning",
	"versions",
	"website",
}

// Signature and API related constants.
const (
	signV2Algorithm = "AWS"
)

// AWS S3 Signature V2 calculation rule is give here:

	ErrInvalidCopyDest: {
		Code:           "InvalidRequest",
		Description:    "This copy request is illegal because it is trying to copy an object to itself without changing the object's metadata, storage class, website redirect location or encryption attributes.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidCopySource: {
		Code:           "InvalidArgument",

		"Expires",
		"Cache-Control",
		"Content-Language",
		"Content-Disposition",
		"X-Amz-Object-Lock-Mode",
		"X-Amz-Object-Lock-Retain-Until-Date",
		"X-Amz-Object-Lock-Legal-Hold",
		"X-Amz-Website-Redirect-Location",
		"X-Amz-Meta-",
	}

	// compare metadata on both maps to see if meta is identical
	compareMeta1 := make(map[string]string)
	for k, v := range oi1.UserDefined {
		var found bool