Repository: flutter
Issue: Run `flutter run --verbose`  should stream the output of `pod install --verbose` so useful information is displayed during long operations
Labels: platform-ios,tool,platform-mac,c: proposal,P3,team-ios,triaged-ios


1. when some pod version changed.
2. I run `flutter run --verbose` to see the detail progress.
3. And I found that it's run `pod install`, since these step is so long, it stuck there for a while.
4. I just stop there, and go into /ios/ folder and run `pod install --verbose` myself
5. it seems it will 
Expected result:

Run `flutter run --verbose`  should better run `pod install --verbose`

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**Target Platform:iOS**
**Target OS version/browser:iOS 13**
**Devices:iPhone8**


## Logs

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The bellow log is when I run `pod install --verbose` success in `/ios/` folder by myself, and go back to root folder and run `flutter run --verbose`:
* still I can see the `Running pod install` takes much time
* and the `CocoaPods' output` looks like wait `pod install` finished first. it's better if it can show logs steps by steps just like what `pod install --verbose` do.

```
[ +112 ms] executing: pod --version
[+1118 ms] 1.8.3
[   +5 ms] Running pod install...
[+5138 ms] Running pod install... (completed in 5.1s)
[   +1 ms] CocoaPods' output:
           ↳
[  +16 ms]       Preparing

               Analyzing dependencies

               Inspecting targets to integrate
                 Using `ARCHS` setting to build architectures of target `Pods-Runner`: (``)

               Finding Podfile changes
               ....
```

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```
```

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
[✓] Flutter (Channel beta, v1.9.1+hotfix.4, on Mac OS X 10.14.6 18G95, locale en-CN)
    • Flutter version 1.9.1+hotfix.4 at /Users/jerryzhou/Documents/code/flutter/sdk/flutter
    • Framework revision cc949a8e8b (3 weeks ago), 2019-09-27 15:04:59 -0700
    • Engine revision b863200c37
    • Dart version 2.5.0


[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
    • Android SDK at /Users/jerryzhou/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-28, build-tools 28.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.1, Build version 11A1027
    • CocoaPods version 1.8.3

[✓] Android Studio (version 3.4)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 34.0.2
    • Dart plugin version 183.5901
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[✗] Cannot determine if IntelliJ is installed
    ✗ Directory listing failed

[✓] VS Code (version 1.39.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.5.1

[✓] Connected device (1 available)
    • iPhonejerry • 1daca728d75535c21ced151fc7829191064d0e00 • ios • iOS 13.1.3
```