if meta, ok := metadata.FromIncomingContext(ac.GrpcContext); ok {
			return meta.Get(header)
		}
	} else if ac.Request != nil {
		return ac.Request.Header.Values(header)
	}
	return nil
}

// Caller carries the identity and authentication source of a caller.
type Caller struct {
	AuthSource AuthSource
	Identities []string

	KubernetesInfo KubernetesInfo
}

//
// Internally this function creates 'uploads.json' associated for the
// incoming object at
// '.minio.sys/multipart/bucket/object/uploads.json' on all the
// disks. `uploads.json` carries metadata regarding on-going multipart
// operation(s) on the object.
func (er erasureObjects) newMultipartUpload(ctx context.Context, bucket string, object string, opts ObjectOptions) (*NewMultipartUploadResult, error) {