The request ETag.
getRequestETag(): Uint8Array; setRequestETag(requestETag: Uint8Array): void;
When the class is operating in client mode (i.e., the Listening property is disabled), this property specifies the ETag that should be included in outgoing requests. Leave it empty to prevent an Etag option from being included.
When the class is operating in server mode (i.e., the Listening property is enabled), this property is populated with the ETag included in incoming requests (if any) anytime the Request event fires. It will be empty if an Etag option was not included.
This property is not available at design time.