Connection.UpgradeFrom (Jetty :: Project 9.4.46.v20220331 API)

All Known Implementing Classes:

HttpConnection, HttpConnectionOverHTTP

Enclosing interface:

Connection
```
public static interface Connection.UpgradeFrom
```
Connection implementations implement this interface when they can upgrade from the protocol they speak (for example HTTP/1.1) to a different protocol (e.g. HTTP/2).

See Also:

EndPoint.upgrade(Connection), Connection.UpgradeTo

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.nio.ByteBuffer`	`onUpgradeFrom()`	Invoked during an `upgrade` to produce a buffer containing bytes that have not been consumed by this connection, and that must be consumed by the upgrade-to connection.

- Method Detail
  - onUpgradeFrom
```
java.nio.ByteBuffer onUpgradeFrom()
```
    Invoked during an upgrade to produce a buffer containing bytes that have not been consumed by this connection, and that must be consumed by the upgrade-to connection.
    
    Returns:
    
    a buffer of unconsumed bytes to pass to the upgrade-to connection. The buffer does not belong to any pool and should be discarded after having consumed its bytes. The returned buffer may be null if there are no unconsumed bytes.