id<GRXWriter> -> GRXWriter * in the runtime

src/objective-c/GRPCClient/GRPCCall.h

@@ -89,7 +89,7 @@ extern id const kGRPCStatusMetadataKey;
 // To finish a call right away, invoke cancel.
 - (instancetype)initWithHost:(NSString *)host
                         path:(NSString *)path
-              requestsWriter:(id<GRXWriter>)requestsWriter NS_DESIGNATED_INITIALIZER;
+              requestsWriter:(GRXWriter *)requestsWriter NS_DESIGNATED_INITIALIZER;
 
 // Finishes the request side of this call, notifies the server that the RPC
 // should be cancelled, and finishes the response side of the call with an error

src/objective-c/GRPCClient/GRPCCall.m

@@ -79,7 +79,7 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
   // all. This wrapper over our actual writeable ensures thread-safety and
   // correct ordering.
   GRPCDelegateWrapper *_responseWriteable;
-  id<GRXWriter> _requestWriter;
+  GRXWriter *_requestWriter;
 
   NSMutableDictionary *_requestMetadata;
   NSMutableDictionary *_responseMetadata;
@@ -94,7 +94,7 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
 // Designated initializer
 - (instancetype)initWithHost:(NSString *)host
                         path:(NSString *)path
-              requestsWriter:(id<GRXWriter>)requestWriter {
+              requestsWriter:(GRXWriter *)requestWriter {
   if (!host || !path) {
     [NSException raise:NSInvalidArgumentException format:@"Neither host nor method can be nil."];
   }

src/objective-c/GRPCClient/private/GRPCDelegateWrapper.h

@@ -54,7 +54,7 @@
 // writesFinishedWithError: is sent to the writeable, and released after that.
 // This is used to create a retain cycle that keeps both objects alive until the
 // writing is explicitly finished.
-- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable writer:(id<GRXWriter>)writer
+- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable writer:(GRXWriter *)writer
     NS_DESIGNATED_INITIALIZER;
 
 // Enqueues writeValue: to be sent to the writeable in the main thread.

src/objective-c/GRPCClient/private/GRPCDelegateWrapper.m

@@ -38,7 +38,7 @@
 @interface GRPCDelegateWrapper ()
 // These are atomic so that cancellation can nillify them from any thread.
 @property(atomic, strong) id<GRXWriteable> writeable;
-@property(atomic, strong) id<GRXWriter> writer;
+@property(atomic, strong) GRXWriter *writer;
 @end
 
 @implementation GRPCDelegateWrapper {
@@ -52,7 +52,7 @@
 }
 
 // Designated initializer
-- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable writer:(id<GRXWriter>)writer {
+- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable writer:(GRXWriter *)writer {
   if (self = [super init]) {
     _writeableQueue = dispatch_get_main_queue();
     _writeable = writeable;

src/objective-c/ProtoRPC/ProtoRPC.h

@@ -40,7 +40,7 @@
 
 - (instancetype)initWithHost:(NSString *)host
                       method:(ProtoMethod *)method
-              requestsWriter:(id<GRXWriter>)requestsWriter
+              requestsWriter:(GRXWriter *)requestsWriter
                responseClass:(Class)responseClass
           responsesWriteable:(id<GRXWriteable>)responsesWriteable NS_DESIGNATED_INITIALIZER;
 

src/objective-c/ProtoRPC/ProtoRPC.m

@@ -46,7 +46,7 @@
 #pragma clang diagnostic ignored "-Wobjc-designated-initializers"
 - (instancetype)initWithHost:(NSString *)host
                         path:(NSString *)path
-              requestsWriter:(id<GRXWriter>)requestsWriter {
+              requestsWriter:(GRXWriter *)requestsWriter {
   [NSException raise:NSInvalidArgumentException
               format:@"Please use ProtoRPC's designated initializer instead."];
   return nil;
@@ -56,7 +56,7 @@
 // Designated initializer
 - (instancetype)initWithHost:(NSString *)host
                       method:(ProtoMethod *)method
-              requestsWriter:(id<GRXWriter>)requestsWriter
+              requestsWriter:(GRXWriter *)requestsWriter
                responseClass:(Class)responseClass
           responsesWriteable:(id<GRXWriteable>)responsesWriteable {
   // Because we can't tell the type system to constrain the class, we need to check at runtime:

src/objective-c/ProtoRPC/ProtoService.h

@@ -35,7 +35,7 @@
 
 @class ProtoRPC;
 @protocol GRXWriteable;
-@protocol GRXWriter;
+@class GRXWriter;
 
 @interface ProtoService : NSObject
 - (instancetype)initWithHost:(NSString *)host
@@ -43,7 +43,7 @@
                  serviceName:(NSString *)serviceName NS_DESIGNATED_INITIALIZER;
 
 - (ProtoRPC *)RPCToMethod:(NSString *)method
-           requestsWriter:(id<GRXWriter>)requestsWriter
+           requestsWriter:(GRXWriter *)requestsWriter
   	        responseClass:(Class)responseClass
   	   responsesWriteable:(id<GRXWriteable>)responsesWriteable;
 @end

src/objective-c/ProtoRPC/ProtoService.m

@@ -66,7 +66,7 @@
 }
 
 - (ProtoRPC *)RPCToMethod:(NSString *)method
-           requestsWriter:(id<GRXWriter>)requestsWriter
+           requestsWriter:(GRXWriter *)requestsWriter
             responseClass:(Class)responseClass
        responsesWriteable:(id<GRXWriteable>)responsesWriteable {
   ProtoMethod *methodName = [[ProtoMethod alloc] initWithPackage:_packageName

src/objective-c/RxLibrary/GRXForwardingWriter.h

@@ -39,5 +39,5 @@
 // input writer, and for classes that represent objects with input and
 // output sequences of values, like an RPC.
 @interface GRXForwardingWriter : GRXWriter
-- (instancetype)initWithWriter:(id<GRXWriter>)writer NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithWriter:(GRXWriter *)writer NS_DESIGNATED_INITIALIZER;
 @end

src/objective-c/RxLibrary/GRXForwardingWriter.m

@@ -37,7 +37,7 @@
 @end
 
 @implementation GRXForwardingWriter {
-  id<GRXWriter> _writer;
+  GRXWriter *_writer;
   id<GRXWriteable> _writeable;
 }
 
@@ -46,7 +46,7 @@
 }
 
 // Designated initializer
-- (instancetype)initWithWriter:(id<GRXWriter>)writer {
+- (instancetype)initWithWriter:(GRXWriter *)writer {
   if (!writer) {
     [NSException raise:NSInvalidArgumentException format:@"writer can't be nil."];
   }
@@ -68,7 +68,7 @@
 // This is used to stop the input writer. It nillifies our reference to it
 // to release it.
 - (void)finishInput {
-  id<GRXWriter> writer = _writer;
+  GRXWriter *writer = _writer;
   _writer = nil;
   writer.state = GRXWriterStateFinished;
 }

src/objective-c/RxLibrary/GRXImmediateWriter.h

@@ -44,11 +44,11 @@
 
 // Returns a writer that pulls values from the passed NSEnumerator instance and pushes them to
 // its writeable. The NSEnumerator is released when it finishes.
-+ (id<GRXWriter>)writerWithEnumerator:(NSEnumerator *)enumerator;
++ (GRXWriter *)writerWithEnumerator:(NSEnumerator *)enumerator;
 
 // Returns a writer that pushes to its writeable the successive values returned by the passed
 // block. When the block first returns nil, it is released.
-+ (id<GRXWriter>)writerWithValueSupplier:(id (^)())block;
++ (GRXWriter *)writerWithValueSupplier:(id (^)())block;
 
 // Returns a writer that iterates over the values of the passed container and pushes them to
 // its writeable. The container is released when the iteration is over.
@@ -56,18 +56,18 @@
 // Note that the usual speed gain of NSFastEnumeration over NSEnumerator results from not having to
 // call one method per element. Because GRXWriteable instances accept values one by one, that speed
 // gain doesn't happen here.
-+ (id<GRXWriter>)writerWithContainer:(id<NSFastEnumeration>)container;
++ (GRXWriter *)writerWithContainer:(id<NSFastEnumeration>)container;
 
 // Returns a writer that sends the passed value to its writeable and then finishes (releasing the
 // value).
-+ (id<GRXWriter>)writerWithValue:(id)value;
++ (GRXWriter *)writerWithValue:(id)value;
 
 // Returns a writer that, as part of its start method, sends the passed error to the writeable
 // (then releasing the error).
-+ (id<GRXWriter>)writerWithError:(NSError *)error;
++ (GRXWriter *)writerWithError:(NSError *)error;
 
 // Returns a writer that, as part of its start method, finishes immediately without sending any
 // values to its writeable.
-+ (id<GRXWriter>)emptyWriter;
++ (GRXWriter *)emptyWriter;
 
 @end

src/objective-c/RxLibrary/GRXImmediateWriter.m

@@ -63,19 +63,19 @@
   return [[self alloc] initWithEnumerator:enumerator error:errorOrNil];
 }
 
-+ (id<GRXWriter>)writerWithEnumerator:(NSEnumerator *)enumerator {
++ (GRXWriter *)writerWithEnumerator:(NSEnumerator *)enumerator {
   return [self writerWithEnumerator:enumerator error:nil];
 }
 
-+ (id<GRXWriter>)writerWithValueSupplier:(id (^)())block {
++ (GRXWriter *)writerWithValueSupplier:(id (^)())block {
   return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithValueSupplier:block]];
 }
 
-+ (id<GRXWriter>)writerWithContainer:(id<NSFastEnumeration>)container {
++ (GRXWriter *)writerWithContainer:(id<NSFastEnumeration>)container {
   return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithContainer:container]];;
 }
 
-+ (id<GRXWriter>)writerWithValue:(id)value {
++ (GRXWriter *)writerWithValue:(id)value {
   if (value) {
     return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithSingleValue:value]];
   } else {
@@ -83,7 +83,7 @@
   }
 }
 
-+ (id<GRXWriter>)writerWithError:(NSError *)error {
++ (GRXWriter *)writerWithError:(NSError *)error {
   if (error) {
     return [self writerWithEnumerator:nil error:error];
   } else {
@@ -91,7 +91,7 @@
   }
 }
 
-+ (id<GRXWriter>)emptyWriter {
++ (GRXWriter *)emptyWriter {
   static GRXImmediateWriter *emptyWriter;
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{

src/objective-c/RxLibrary/transformations/GRXMappingWriter.h

@@ -35,6 +35,6 @@
 
 // A "proxy" writer that transforms all the values of its input writer by using a mapping function.
 @interface GRXMappingWriter : GRXForwardingWriter
-- (instancetype)initWithWriter:(id<GRXWriter>)writer map:(id (^)(id value))map
+- (instancetype)initWithWriter:(GRXWriter *)writer map:(id (^)(id value))map
     NS_DESIGNATED_INITIALIZER;
 @end

src/objective-c/RxLibrary/transformations/GRXMappingWriter.m

@@ -44,12 +44,12 @@ static id (^kIdentity)(id value) = ^id(id value) {
   id (^_map)(id value);
 }
 
-- (instancetype)initWithWriter:(id<GRXWriter>)writer {
+- (instancetype)initWithWriter:(GRXWriter *)writer {
   return [self initWithWriter:writer map:nil];
 }
 
 // Designated initializer
-- (instancetype)initWithWriter:(id<GRXWriter>)writer map:(id (^)(id value))map {
+- (instancetype)initWithWriter:(GRXWriter *)writer map:(id (^)(id value))map {
   if ((self = [super initWithWriter:writer])) {
     _map = map ?: kIdentity;
   }