Add the reset access

mockrxandroidble/src/main/java/com/polidea/rxandroidble2/mockrxandroidble/RxBleConnectionMock.java

@@ -100,6 +100,11 @@ public Single<RxBleDeviceServices> discoverServices(long timeout, @NonNull TimeU
         return Single.just(rxBleDeviceServices);
     }
 
+    @Override
+    public Single<RxBleDeviceServices> discoverServices(long timeout, @NonNull TimeUnit timeUnit, Boolean clearCache) {
+        return Single.just(rxBleDeviceServices);
+    }
+
     @Override
     public Single<BluetoothGattCharacteristic> getCharacteristic(@NonNull final UUID characteristicUuid) {
         return discoverServices()

rxandroidble/src/main/java/com/polidea/rxandroidble2/RxBleConnection.java

@@ -266,6 +266,24 @@ interface WriteOperationAckStrategy extends ObservableTransformer<Boolean, Boole
      */
     Single<RxBleDeviceServices> discoverServices(@IntRange(from = 1) long timeout, @NonNull TimeUnit timeUnit);
 
+    /**
+     * Performs GATT service discovery and emits discovered results. After service discovery you can walk through
+     * {@link android.bluetooth.BluetoothGattService}s and {@link BluetoothGattCharacteristic}s.
+     * <p>
+     * Result of the discovery is cached internally so consecutive calls won't trigger BLE operation and can be
+     * considered relatively lightweight.
+     *
+     * Timeouts after specified amount of time.
+     *
+     * @param timeout multiplier of TimeUnit after which the discovery will timeout in case of no return values
+     * @param timeUnit TimeUnit for the timeout
+     * @return Observable emitting result a GATT service discovery.
+     * @throws BleGattCannotStartException with {@link BleGattOperationType#SERVICE_DISCOVERY} type, when it wasn't possible to start
+     *                                     the discovery for internal reasons.
+     * @throws BleGattException            in case of GATT operation error with {@link BleGattOperationType#SERVICE_DISCOVERY} type.
+     */
+    Single<RxBleDeviceServices> discoverServices(@IntRange(from = 1) long timeout, @NonNull TimeUnit timeUnit, Boolean clearCache);
+
     /**
      * @see #setupNotification(UUID, NotificationSetupMode)  with default setup mode.
      */

rxandroidble/src/main/java/com/polidea/rxandroidble2/internal/connection/RxBleConnectionImpl.java

@@ -138,6 +138,11 @@ public Single<RxBleDeviceServices> discoverServices(long timeout, @NonNull TimeU
         return serviceDiscoveryManager.getDiscoverServicesSingle(timeout, timeUnit);
     }
 
+    @Override
+    public Single<RxBleDeviceServices> discoverServices(long timeout, @NonNull TimeUnit timeUnit, Boolean clearCache) {
+        return serviceDiscoveryManager.getDiscoverServicesSingle(timeout, timeUnit, clearCache);
+    }
+
     @Override
     @Deprecated
     public Single<BluetoothGattCharacteristic> getCharacteristic(@NonNull final UUID characteristicUuid) {

rxandroidble/src/main/java/com/polidea/rxandroidble2/internal/connection/ServiceDiscoveryManager.java

@@ -61,6 +61,24 @@ public void accept(Disposable disposable) throws Exception {
         }
     }
 
+    Single<RxBleDeviceServices> getDiscoverServicesSingle(final long timeout, final TimeUnit timeoutTimeUnit, Boolean clearCache) {
+        if (hasCachedResults) {
+            // optimisation to decrease the number of allocations
+            return deviceServicesObservable;
+        } else {
+            if (clearCache) {
+                reset();
+            }
+            return deviceServicesObservable.doOnSubscribe(
+                    new Consumer<Disposable>() {
+                        @Override
+                        public void accept(Disposable disposable) throws Exception {
+                            timeoutBehaviorSubject.onNext(new TimeoutConfiguration(timeout, timeoutTimeUnit, Schedulers.computation()));
+                        }
+                    });
+        }
+    }
+
     private void reset() {
         hasCachedResults = false;
         this.deviceServicesObservable = getListOfServicesFromGatt()