propagate availability guards (#1706)

Tests/GRPCCoreTests/Call/Client/Internal/ClientRPCExecutorTestSupport/ClientRPCExecutorTestHarness+Transport.swift

@@ -19,7 +19,7 @@ import Atomics
 
 // TODO: replace with real in-process transport
 
-@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 final class TestingClientTransport: ClientTransport, Sendable {
   typealias Inbound = RPCAsyncSequence<RPCResponsePart>
   typealias Outbound = RPCWriter<RPCRequestPart>.Closable
@@ -131,7 +131,7 @@ final class TestingClientTransport: ClientTransport, Sendable {
   }
 }
 
-@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 final class TestingServerTransport: ServerTransport, Sendable {
   typealias Inbound = RPCAsyncSequence<RPCRequestPart>
   typealias Outbound = RPCWriter<RPCResponsePart>.Closable

Tests/GRPCCoreTests/Call/Client/Internal/ClientRPCExecutorTestSupport/ClientRPCExecutorTestHarness.swift

@@ -24,7 +24,7 @@ import XCTest
 /// of the server to allow for flexible testing scenarios with minimal boilerplate. The harness
 /// also tracks how many streams the client has opened, how many streams the server accepted, and
 /// how many streams the client failed to open.
-@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 struct ClientRPCExecutorTestHarness {
   private let server: ServerStreamHandler
   private let clientTransport: StreamCountingClientTransport

Tests/GRPCCoreTests/Call/Client/Internal/ClientRPCExecutorTestSupport/ClientRPCExecutorTestHasness+ServerBehavior.swift

@@ -18,7 +18,7 @@ import XCTest
 
 @testable import GRPCCore
 
-@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 extension ClientRPCExecutorTestHarness {
   struct ServerStreamHandler: Sendable {
     private let handler:
@@ -48,7 +48,7 @@ extension ClientRPCExecutorTestHarness {
   }
 }
 
-@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 extension ClientRPCExecutorTestHarness.ServerStreamHandler {
   static var echo: Self {
     return Self {

Tests/GRPCCoreTests/Call/Client/Internal/ClientRPCExecutorTests.swift

@@ -16,7 +16,7 @@
 import GRPCCore
 import XCTest
 
-@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 final class ClientRPCExecutorTests: XCTestCase {
   func testUnaryEcho() async throws {
     let tester = ClientRPCExecutorTestHarness(server: .echo)

Tests/GRPCCoreTests/Test Utilities/Transport/AnyTransport.swift

@@ -15,6 +15,7 @@
  */
 @testable import GRPCCore
 
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 struct AnyClientTransport: ClientTransport, Sendable {
   typealias Inbound = RPCAsyncSequence<RPCResponsePart>
   typealias Outbound = RPCWriter<RPCRequestPart>.Closable
@@ -74,6 +75,7 @@ struct AnyClientTransport: ClientTransport, Sendable {
   }
 }
 
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
 struct AnyServerTransport: ServerTransport, Sendable {
   typealias Inbound = RPCAsyncSequence<RPCRequestPart>
   typealias Outbound = RPCWriter<RPCResponsePart>.Closable

Tests/GRPCCoreTests/Test Utilities/Transport/StreamCountingTransport.swift

@@ -17,6 +17,7 @@ import Atomics
 
 @testable import GRPCCore
 
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 struct StreamCountingClientTransport: ClientTransport, Sendable {
   typealias Inbound = RPCAsyncSequence<RPCResponsePart>
   typealias Outbound = RPCWriter<RPCRequestPart>.Closable
@@ -69,6 +70,7 @@ struct StreamCountingClientTransport: ClientTransport, Sendable {
   }
 }
 
+@available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
 struct StreamCountingServerTransport: ServerTransport, Sendable {
   typealias Inbound = RPCAsyncSequence<RPCRequestPart>
   typealias Outbound = RPCWriter<RPCResponsePart>.Closable

Tests/GRPCCoreTests/Test Utilities/Transport/ThrowingTransport.swift

@@ -15,6 +15,7 @@
  */
 @testable import GRPCCore
 
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 struct ThrowOnStreamCreationTransport: ClientTransport {
   typealias Inbound = RPCAsyncSequence<RPCResponsePart>
   typealias Outbound = RPCWriter<RPCRequestPart>.Closable