rpc: handle response with Identify opcode as retryable

Sometimes arRPC would just send a response with the Identify opcode and `{"cmd":""}`. It is unclear what causes this and the easiest way to recover that I'm aware of is to close the connection and start a fresh one.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

rpc.go

@@ -146,8 +146,18 @@ func validateRaw[T nonceEventCommandTracer](opcode uint32, event, command, nonce
 		if err == nil {
 			switch {
 			case opcodeR != opcode:
+				// the socket is still open however
+				// as far as I'm aware this state is not recoverable
+				// therefore we close the connection and advise a retry
+				if opcodeR == Identify {
+					// clean up as much as possible
+					_ = d.Close()
+					// advise retry
+					err = ErrAgain
+				} else {
 					debugResponse(resp)
 					err = fmt.Errorf("received unexpected opcode %d", opcodeR)
+				}
 			case !resp.nonce(nonce):
 				err = ErrNonce
 			case eventR != nil: