Add a way for a client to know if the device cache is primed in Darwin (project-chip#32556)

* Initial commit

* Restyled by whitespace

* Restyled by clang-format

* Update src/darwin/Framework/CHIP/MTRDevice.mm

Co-authored-by: Anush Nadathur <anush@apple.com>

* Update src/darwin/Framework/CHIP/MTRDevice.h

Co-authored-by: Karsten Sperling <113487422+ksperling-apple@users.noreply.github.com>

* Adding header

* Restyled by clang-format

---------

Co-authored-by: Restyled.io <commits@restyled.io>
Co-authored-by: Anush Nadathur <anush@apple.com>
Co-authored-by: Karsten Sperling <113487422+ksperling-apple@users.noreply.github.com>

Author: 4 people

src/darwin/Framework/CHIP/MTRDevice.h

@@ -64,6 +64,14 @@ MTR_AVAILABLE(ios(16.1), macos(13.0), watchos(9.1), tvos(16.1))
  */
 @property (nonatomic, readonly) MTRDeviceState state;
 
+/**
+ * Is the state cache primed for this device?
+ *
+ * This verifies that both the MTRDeviceController has a storage delegate, and a subscription has been set up and the resulting state has been cached. If this is true this means most state is ready to cache and will not require a round trip to the accessory.
+ *
+ */
+@property (readonly) BOOL deviceCachePrimed;
+
 /**
  * The estimated device system start time.
  *

src/darwin/Framework/CHIP/MTRDevice.mm

@@ -33,6 +33,7 @@
 #import "MTRError_Internal.h"
 #import "MTREventTLVValueDecoder_Internal.h"
 #import "MTRLogging_Internal.h"
+#import "MTRUnfairLock.h"
 #import "zap-generated/MTRCommandPayloads_Internal.h"
 
 #include "lib/core/CHIPError.h"
@@ -2017,6 +2018,12 @@ - (void)setAttributeValues:(NSArray<NSDictionary *> *)attributeValues reportChan
     os_unfair_lock_unlock(&self->_lock);
 }
 
+- (BOOL)deviceCachePrimed
+{
+    std::lock_guard lock(_lock);
+    return [self _isCachePrimedWithInitialConfigurationData];
+}
+
 // If value is non-nil, associate with expectedValueID
 // If value is nil, remove only if expectedValueID matches
 // previousValue is an out parameter