Add connection latency windows

gap.go

@@ -586,6 +586,19 @@ func (buf *rawAdvertisementPayload) addServiceUUID(uuid UUID) (ok bool) {
 	}
 }
 
+type ConnectionLatency uint8
+
+const (
+	// A latency setting that uses the default connection parameters of the system.
+	ConnectionLatencyDefault ConnectionLatency = 0
+	// A latency setting indicating that prioritizes rapid communication over battery life.
+	ConnectionLatencyLow ConnectionLatency = 1
+	// A latency setting that balances communication frequency and battery life.
+	ConnectionLatencyMedium ConnectionLatency = 2
+	// A latency setting that prioritizes extending battery life over rapid communication.
+	ConnectionLatencyHigh ConnectionLatency = 3
+)
+
 // ConnectionParams are used when connecting to a peripherals or when changing
 // the parameters of an active connection.
 type ConnectionParams struct {
@@ -604,4 +617,14 @@ type ConnectionParams struct {
 	// communication, the connection is considered lost. If no timeout is
 	// specified, the timeout will be unchanged.
 	Timeout Duration
+
+	// Latency setting. This is a high-level setting that indicates whether the connection should
+	// prioritize rapid communication or battery life.
+	//
+	// Some platforms (e.g. Windows) may not support setting the connection parameters directly,
+	// but may support setting a latency level that corresponds to a set of connection parameters.
+	// In this case, the Latency field can be used to set the latency level instead of setting the connection parameters directly.
+	//
+	// If no latency is specified, the latency will be unchanged.
+	Latency ConnectionLatency
 }

gap_windows.go

@@ -433,13 +433,41 @@ func (d Device) Disconnect() error {
 // Whether or not the device will actually honor this, depends on the device and
 // on the specific parameters.
 //
-// On Windows, this call doesn't do anything.
+// On Windows, only the latency level can be set, since Windows does not support setting the connection parameters directly.
+// If a latency level is specified, the corresponding latency level will be set on the connection.
+// If no latency level is specified, the latency level will be left unchanged.
 func (d Device) RequestConnectionParams(params ConnectionParams) error {
-	// TODO: implement this using
-	// BluetoothLEDevice.RequestPreferredConnectionParameters.
+	pref, err := preferredConnectionParametersFromConnectionParams(params)
+	if err != nil {
+		return err
+	}
+
+	// The user has requested a specific connection latency
+	if pref != nil {
+		_, err = d.device.RequestPreferredConnectionParameters(pref)
+		if err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
+func preferredConnectionParametersFromConnectionParams(params ConnectionParams) (*bluetooth.BluetoothLEPreferredConnectionParameters, error) {
+	switch params.Latency {
+	case ConnectionLatencyDefault:
+		return nil, nil
+	case ConnectionLatencyLow:
+		return bluetooth.BluetoothLEPreferredConnectionParametersGetThroughputOptimized()
+	case ConnectionLatencyMedium:
+		return bluetooth.BluetoothLEPreferredConnectionParametersGetBalanced()
+	case ConnectionLatencyHigh:
+		return bluetooth.BluetoothLEPreferredConnectionParametersGetPowerOptimized()
+	default:
+		return nil, fmt.Errorf("invalid latency value: %d", params.Latency)
+	}
+}
+
 // SetRandomAddress sets the random address to be used for advertising.
 func (a *Adapter) SetRandomAddress(mac MAC) error {
 	return errors.ErrUnsupported

go.mod

@@ -5,7 +5,7 @@ go 1.22.1
 require (
 	github.com/go-ole/go-ole v1.2.6
 	github.com/godbus/dbus/v5 v5.1.0
-	github.com/saltosystems/winrt-go v0.0.0-20240509164145-4f7860a3bd2b
+	github.com/saltosystems/winrt-go v0.0.0-20260309155547-a4512e2b5ee5
 	github.com/soypat/cyw43439 v0.0.0-20250505012923-830110c8f4af
 	github.com/tinygo-org/cbgo v0.0.4
 	golang.org/x/crypto v0.12.0

go.sum

@@ -12,6 +12,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/saltosystems/winrt-go v0.0.0-20240509164145-4f7860a3bd2b h1:du3zG5fd8snsFN6RBoLA7fpaYV9ZQIsyH9snlk2Zvik=
 github.com/saltosystems/winrt-go v0.0.0-20240509164145-4f7860a3bd2b/go.mod h1:CIltaIm7qaANUIvzr0Vmz71lmQMAIbGJ7cvgzX7FMfA=
+github.com/saltosystems/winrt-go v0.0.0-20260309155547-a4512e2b5ee5 h1:uWLD1I1ZF6JenjrTSB80JcHp/lXngoG5xuN8dT8Tbvg=
+github.com/saltosystems/winrt-go v0.0.0-20260309155547-a4512e2b5ee5/go.mod h1:CIltaIm7qaANUIvzr0Vmz71lmQMAIbGJ7cvgzX7FMfA=
 github.com/sirupsen/logrus v1.5.0/go.mod h1:+F7Ogzej0PZc/94MaYx/nvG9jOFMD2osvC3s+Squfpo=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=