title: "flutter pub get" can't get dependency plugins
body: <p>I've been trying to get dependencies for my Flutter project on Windows but it's taking a long time and after a while , it shows this error in 'messages' bar.</p>
  
  <pre><code>Running "flutter pub get" in badhan_blood_bank...               
  OS Error: The semaphore timeout period has expired.
  
  , errno = 121, address = storage.googleapis.com, port = 53515
  
  pub get failed (server unavailable) -- attempting retry 1 in 1 second...
  </code></pre>
  
  <p>I am trying to solve this problem some ways but failed to solve.
  I am doing flutter clean, flutter upgrade and restart android studio at the end same problem happen.</p>
  
  <p>It was working fine before I add url_launcher inside the dependencies in my project.</p>
  
  <p>Here is my pubspec.yaml file:</p>
  
  <pre><code>version: 1.0.0+1
  
  environment:
    sdk: "&gt;=2.1.0 &lt;3.0.0"
  
  dependencies:
    flutter:
      sdk: flutter
  
    cupertino_icons: ^0.1.2
    firebase_auth: ^0.15.5+2
    flutter_facebook_login: ^3.0.0
    flutter_icons: ^1.0.0+1
    flutter_spinkit: ^4.1.2
    firebase_database: ^3.1.3
    google_maps_flutter: ^0.5.25
    geolocator: ^5.3.0
    intl: ^0.16.1
    curved_navigation_bar: ^0.3.2
    fluttertoast: ^4.0.1
    url_launcher: ^5.4.2
  
  
  
  dev_dependencies:
    flutter_test:
      sdk: flutter
  
  flutter:
    uses-material-design: true
  
    assets:
    - images/
  </code></pre>
  
  <p><br></p>
  
  <p>After running "flutter pub get --verbose" shows:</p>
  
  <pre><code>[  +27 ms] executing: [C:\src\flutter\flutter\] git -c log.showSignature=false log -n 1 --pretty=format:%H
  [  +64 ms] Exit code 0 from: git -c log.showSignature=false log -n 1 --pretty=format:%H
  [        ] 0b8abb4724aa590dd0f429683339b1e045a1594d
  [        ] executing: [C:\src\flutter\flutter\] git describe --match v*.*.* --first-parent --long --tags
  [  +56 ms] Exit code 0 from: git describe --match v*.*.* --first-parent --long --tags
  [        ] v1.12.13+hotfix.8-0-g0b8abb472
  [   +7 ms] executing: [C:\src\flutter\flutter\] git rev-parse --abbrev-ref --symbolic @{u}
  [  +41 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic @{u}
  [        ] origin/stable
  [        ] executing: [C:\src\flutter\flutter\] git ls-remote --get-url origin
  [  +38 ms] Exit code 0 from: git ls-remote --get-url origin
  [        ] https://github.com/flutter/flutter.git
  [  +77 ms] executing: [C:\src\flutter\flutter\] git rev-parse --abbrev-ref HEAD
  [  +41 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
  [        ] stable
  [  +48 ms] Artifact Instance of 'AndroidMavenArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
  [   +4 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
  [        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
  [ +130 ms] Running "flutter pub get" in badhan_blood_bank...
  [   +5 ms] Using C:\src\flutter\flutter\.pub-cache for the pub cache.
  [   +1 ms] executing: [D:\@@MyWorks\mahmud\Badhan Blood Bank\badhan_blood_bank\] C:\src\flutter\flutter\bin\cache\dart-sdk\bin\pub.bat --verbose get
  --no-precompile
  [ +157 ms] FINE: Pub 2.7.0
  [   +3 ms] IO  : Spawning "cmd /c ver" in D:\@@MyWorks\mahmud\Badhan Blood Bank\badhan_blood_bank\.
  [   +7 ms] IO  : Finished ver. Exit code 0.
  [   +1 ms]     | stdout:
  [        ]     | | 
  [   +1 ms]     | | Microsoft Windows [Version 10.0.18362.720]
  [   +1 ms]     | Nothing output on stderr.
  [ +102 ms] MSG : Resolving dependencies...
  [   +9 ms] SLVR: fact: badhanbloodbank is 1.0.0+1
  [   +5 ms] SLVR: derived: badhanbloodbank
  [  +61 ms] SLVR: fact: badhanbloodbank depends on flutter any from sdk
  [   +1 ms] SLVR: fact: badhanbloodbank depends on cupertino_icons ^0.1.2
  [   +1 ms] SLVR: fact: badhanbloodbank depends on firebase_auth ^0.15.5+2
  [   +1 ms] SLVR: fact: badhanbloodbank depends on flutter_facebook_login ^3.0.0
  [   +1 ms] SLVR: fact: badhanbloodbank depends on flutter_icons ^1.0.0+1
  [   +1 ms] SLVR: fact: badhanbloodbank depends on flutter_spinkit ^4.1.2
  [        ] SLVR: fact: badhanbloodbank depends on firebase_database ^3.1.3
  [        ] SLVR: fact: badhanbloodbank depends on google_maps_flutter ^0.5.25
  [        ] SLVR: fact: badhanbloodbank depends on geolocator ^5.3.0
  [        ] SLVR: fact: badhanbloodbank depends on intl ^0.16.1
  [        ] SLVR: fact: badhanbloodbank depends on curved_navigation_bar ^0.3.2
  [        ] SLVR: fact: badhanbloodbank depends on fluttertoast ^4.0.1
  [        ] SLVR: fact: badhanbloodbank depends on url_launcher ^5.4.2
  [        ] SLVR: fact: badhanbloodbank depends on flutter_test any from sdk
  [        ] SLVR:   selecting badhanbloodbank
  [        ] SLVR:   derived: flutter_test any from sdk
  [        ] SLVR:   derived: url_launcher ^5.4.2
  [   +1 ms] SLVR:   derived: fluttertoast ^4.0.1
  [   +1 ms] SLVR:   derived: curved_navigation_bar ^0.3.2
  [        ] SLVR:   derived: intl ^0.16.1
  [   +1 ms] SLVR:   derived: geolocator ^5.3.0
  [   +1 ms] SLVR:   derived: google_maps_flutter ^0.5.25
  [   +1 ms] SLVR:   derived: firebase_database ^3.1.3
  [        ] SLVR:   derived: flutter_spinkit ^4.1.2
  [        ] SLVR:   derived: flutter_icons ^1.0.0+1
  [        ] SLVR:   derived: flutter_facebook_login ^3.0.0
  [        ] SLVR:   derived: firebase_auth ^0.15.5+2
  [        ] SLVR:   derived: cupertino_icons ^0.1.2
  [        ] SLVR:   derived: flutter any from sdk
  [        ] IO  : Get versions from https://pub.dartlang.org/api/packages/url_launcher.
  [   +9 ms] IO  : HTTP GET https://pub.dartlang.org/api/packages/url_launcher
  [   +2 ms]     | Accept: application/vnd.pub.v2+json
  [   +1 ms]     | X-Pub-OS: windows
  [        ]     | X-Pub-Command: get
  [        ]     | X-Pub-Session-ID: 795584D9-523C-4575-B686-2D496C324C5B
  [        ]     | X-Pub-Environment: flutter_cli:get
  [   +1 ms]     | X-Pub-Reason: direct
  [        ]     | user-agent: Dart pub 2.7.0
  [ +934 ms] IO  : HTTP response 200 OK for GET https://pub.dartlang.org/api/packages/url_launcher
  [   +5 ms]     | took 0:00:00.938247
  [   +2 ms]     | transfer-encoding: chunked
  [   +2 ms]     | date: Sun, 29 Mar 2020 19:47:07 GMT
  [   +2 ms]     | content-encoding: gzip
  [   +2 ms]     | vary: Accept-Encoding
  [   +3 ms]     | strict-transport-security: max-age=31536000; preload
  [   +3 ms]     | via: 1.1 google
  [   +2 ms]     | content-type: application/json
  [   +2 ms]     | x-frame-options: SAMEORIGIN
  [   +2 ms]     | x-xss-protection: 1; mode=block
  [   +2 ms]     | x-content-type-options: nosniff
  [   +2 ms]     | server: dart:io with Shelf
  [  +66 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on flutter any from sdk
  [   +1 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on test_api 0.2.11
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on path 1.6.4
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on image 2.1.4
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on quiver 2.0.5
  [   +1 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on stack_trace 1.9.3
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on vector_math 2.0.8
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on archive 2.0.11
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on args 1.5.2
  [   +1 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on async 2.4.0
  [   +1 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on boolean_selector 1.0.5
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on charcode 1.1.2
  [   +1 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on collection 1.14.11
  [   +1 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on convert 2.1.1
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on crypto 2.1.3
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on matcher 0.12.6
  [   +2 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on meta 1.1.8
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on pedantic 1.8.0+1
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on petitparser 2.4.0
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on source_span 1.5.5
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on stream_channel 2.0.0
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on string_scanner 1.0.5
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on term_glyph 1.1.0
  [        ] SLVR:   fact: flutter_test 0.0.0 from sdk depends on typed_data 1.1.6
  [   +1 ms] SLVR:   fact: flutter_test 0.0.0 from sdk depends on xml 3.5.0
  [        ] SLVR:     selecting flutter_test 0.0.0 from sdk
  [        ] SLVR:     derived: xml 3.5.0
  [        ] SLVR:     derived: typed_data 1.1.6
  [   +1 ms] SLVR:     derived: term_glyph 1.1.0
  [        ] SLVR:     derived: string_scanner 1.0.5
  [        ] SLVR:     derived: stream_channel 2.0.0
  [   +2 ms] SLVR:     derived: source_span 1.5.5
  [        ] SLVR:     derived: petitparser 2.4.0
  [        ] SLVR:     derived: pedantic 1.8.0+1
  [        ] SLVR:     derived: meta 1.1.8
  [   +3 ms] SLVR:     derived: matcher 0.12.6
  [        ] SLVR:     derived: crypto 2.1.3
  [        ] SLVR:     derived: convert 2.1.1
  [   +1 ms] SLVR:     derived: collection 1.14.11
  [        ] SLVR:     derived: charcode 1.1.2
  [        ] SLVR:     derived: boolean_selector 1.0.5
  [        ] SLVR:     derived: async 2.4.0
  [   +1 ms] SLVR:     derived: args 1.5.2
  [   +4 ms] SLVR:     derived: archive 2.0.11
  [   +1 ms] SLVR:     derived: vector_math 2.0.8
  [   +4 ms] SLVR:     derived: stack_trace 1.9.3
  [   +1 ms] SLVR:     derived: quiver 2.0.5
  [        ] SLVR:     derived: image 2.1.4
  [   +1 ms] SLVR:     derived: path 1.6.4
  [   +1 ms] SLVR:     derived: test_api 0.2.11
  [   +1 ms] SLVR:     fact: url_launcher &gt;=3.0.0 depends on flutter any from sdk
  [        ] SLVR:     fact: url_launcher &gt;=5.4.0 depends on url_launcher_macos ^0.0.1
  [   +1 ms] SLVR:     fact: url_launcher &gt;=5.4.1 depends on url_launcher_platform_interface ^1.0.4
  [   +1 ms] SLVR:     fact: url_launcher &gt;=5.3.0 depends on url_launcher_web ^0.1.0+1
  [   +1 ms] SLVR:       selecting url_launcher 5.4.2
  [        ] SLVR:       derived: url_launcher_web ^0.1.0+1
  [        ] SLVR:       derived: url_launcher_platform_interface ^1.0.4
  [        ] SLVR:       derived: url_launcher_macos ^0.0.1
  [   +1 ms] IO  : Get versions from https://pub.dartlang.org/api/packages/url_launcher_web.
  [   +1 ms] IO  : HTTP GET https://pub.dartlang.org/api/packages/url_launcher_web
  [        ]     | Accept: application/vnd.pub.v2+json
  [        ]     | X-Pub-OS: windows
  [        ]     | X-Pub-Command: get
  [        ]     | X-Pub-Session-ID: 795584D9-523C-4575-B686-2D496C324C5B
  [        ]     | X-Pub-Environment: flutter_cli:get
  [        ]     | user-agent: Dart pub 2.7.0
  [ +429 ms] IO  : HTTP response 200 OK for GET https://pub.dartlang.org/api/packages/url_launcher_web
  
  </code></pre>
  
  <p><strong>What is the problem and how to solve it?</strong></p>