Make multiple -init and +new UNAVAILABLE; identify designated initializer

src/objective-c/GRPCClient/GRPCCall.h

@@ -190,8 +190,10 @@ extern id const kGRPCTrailersKey;
 
 - (instancetype)init NS_UNAVAILABLE;
 
++ (instancetype)new NS_UNAVAILABLE;
+
 /** Initialize with all properties. */
-- (instancetype)initWithHost:(NSString *)host path:(NSString *)path safety:(GRPCCallSafety)safety;
+- (instancetype)initWithHost:(NSString *)host path:(NSString *)path safety:(GRPCCallSafety)safety NS_DESIGNATED_INITIALIZER;
 
 /** The host serving the RPC service. */
 @property(copy, readonly) NSString *host;
@@ -214,6 +216,8 @@ extern id const kGRPCTrailersKey;
 
 - (instancetype)init NS_UNAVAILABLE;
 
++ (instancetype)new NS_UNAVAILABLE;
+
 /**
  * Designated initializer for a call.
  * \param requestOptions Protobuf generated parameters for the call.

src/objective-c/ProtoRPC/ProtoRPC.h

@@ -26,6 +26,10 @@
 /** A unary-request RPC call with Protobuf. */
 @interface GRPCUnaryProtoCall : NSObject
 
+- (instancetype)init NS_UNAVAILABLE;
+
++ (instancetype)new NS_UNAVAILABLE;
+
 /**
  * Users should not use this initializer directly. Call objects will be created, initialized, and
  * returned to users by methods of the generated service.
@@ -34,7 +38,7 @@
                                message:(GPBMessage *)message
                        responseHandler:(id<GRPCResponseHandler>)handler
                            callOptions:(GRPCCallOptions *)callOptions
-                         responseClass:(Class)responseClass;
+                         responseClass:(Class)responseClass NS_DESIGNATED_INITIALIZER;
 
 /** Cancel the call at best effort. */
 - (void)cancel;
@@ -44,6 +48,10 @@
 /** A client-streaming RPC call with Protobuf. */
 @interface GRPCStreamingProtoCall : NSObject
 
+- (instancetype)init NS_UNAVAILABLE;
+
++ (instancetype)new NS_UNAVAILABLE;
+
 /**
  * Users should not use this initializer directly. Call objects will be created, initialized, and
  * returned to users by methods of the generated service.
@@ -51,7 +59,7 @@
 - (instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions
                        responseHandler:(id<GRPCResponseHandler>)handler
                            callOptions:(GRPCCallOptions *)callOptions
-                         responseClass:(Class)responseClass;
+                         responseClass:(Class)responseClass NS_DESIGNATED_INITIALIZER;
 
 /** Cancel the call at best effort. */
 - (void)cancel;

src/objective-c/ProtoRPC/ProtoService.h

@@ -30,6 +30,10 @@
 __attribute__((deprecated("Please use GRPCProtoService."))) @interface ProtoService
     : NSObject
 
+- (instancetype)init NS_UNAVAILABLE;
+
++ (instancetype)new NS_UNAVAILABLE;
+
       -
       (instancetype)initWithHost : (NSString *)host packageName
     : (NSString *)packageName serviceName : (NSString *)serviceName callOptions