defaultSha256Cksum = emptySHA256
		v, ok = r.Header[xhttp.AmzContentSha256]
	}

	// We found 'X-Amz-Content-Sha256' return the captured value.
	if ok {
		return v[0]
	}

	// We couldn't find 'X-Amz-Content-Sha256'.
	return defaultSha256Cksum
}

// isValidRegion - verify if incoming region value is valid with configured Region.
func isValidRegion(reqRegion string, confRegion string) bool {

		// we are inside a for loop i.e if we use defer, we would accumulate a lot of open files by the time
		// we return from this function.
		closeBitrotReaders(readers)
		if err != nil {
			// If we have successfully written all the content that was asked
			// by the client, but we still see an error - this would mean
			// that we have some parts or data blocks missing or corrupted

	}

	inputQuery := r.URL.Query()
	// case where some headers need to get from request query
	signedHeaders = append(signedHeaders, "x-amz-server-side-encryption")
	// expect to fail with `ErrUnsignedHeaders` because couldn't find some header
	_, errCode = extractSignedHeaders(signedHeaders, r)
	if errCode != ErrUnsignedHeaders {
		t.Fatalf("Expected the APIErrorCode to %d, but got %d", ErrUnsignedHeaders, errCode)
	}

				if exp.ExpireAll {
					toExpireAll = append(toExpireAll, exp.ObjectInfo)
					continue
				}
				// Cache ObjectInfo value via pointers for
				// subsequent use to track objects which
				// couldn't be deleted.
				od := ObjectToDelete{
					ObjectV: ObjectV{
						ObjectName: exp.Name,
						VersionID:  exp.VersionID,
					},
				}
				toDel = append(toDel, od)
				oiCache.Add(od, &exp.ObjectInfo)

				a.setInt(iA)
			} else if fA, ok := a.bytesToFloat(); ok {
				a.setFloat(fA)
			} else {
				return fmt.Errorf("Could not convert %s to a number", a.String())
			}

		case bool:
			if bA, ok := a.bytesToBool(); ok {
				a.setBool(bA)
			} else {
				return fmt.Errorf("Could not convert %s to a boolean", a.String())
			}

		default:
			return errCmpMismatchedTypes
		}
		return nil

	r := &http.Request{
		Proto:  "HTTP/1.0",
		Method: http.MethodPost,
		URL:    u,
	}
	if !guessIsRPCReq(r) {
		t.Fatal("Test shouldn't fail for a possible net/rpc request.")
	}
	r = &http.Request{
		Proto:  "HTTP/1.1",
		Method: http.MethodGet,
	}
	if guessIsRPCReq(r) {
		t.Fatal("Test shouldn't report as net/rpc for a non net/rpc request.")
	}
	r = &http.Request{
		Proto:  "HTTP/1.1",
		Method: http.MethodGet,

	}

	ignoredErrs := []error{
		errFileNotFound,
		errVolumeNotFound,
		errFileVersionNotFound,
		io.ErrUnexpectedEOF, // some times we would read without locks, ignore these errors
		io.EOF,              // some times we would read without locks, ignore these errors
		context.DeadlineExceeded,
		context.Canceled,
	}
	ignoredErrs = append(ignoredErrs, objectOpIgnoredErrs...)

	errs := g.Wait()

}

// LockedOpenFile - initializes a new lock and protects
// the file from concurrent access across mount points.
// This implementation doesn't support all the open
// flags and shouldn't be considered as replacement
// for os.OpenFile().
func LockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
	return lockedOpenFile(path, flag, perm, 0)
}

// Open - Call os.OpenFile

2018/12/26 17:49:36 listening on http://localhost:8080/
```

> NOTE: for a reasonable test outcome, make sure the assumed user has at least permission/policy to list all buckets. That policy would look like below:

```
{
  "version": "2012-10-17",
  "statement": [
    {
      "effect": "Allow",
      "action": [
        "s3:ListAllMyBuckets"
      ],
      "resource": [

## Concepts

- If an object is under legal hold, it cannot be deleted unless the legal hold is explicitly removed for the respective version id. DeleteObjectVersion() would fail otherwise.