Running in AWS Lambda push error

SETUP:
lambda + apigateway ( /{proxy+} - ANY - Method Execution )
Virtual Private Cloud (VPC) - no VPC

> By default, Lambda runs your functions in a secure VPC with access to AWS services and the internet. When you connect a function to a VPC in your account, it does not have access to the internet unless your VPC provides access.

CloudWatch Logs for lambda

```
time="2019/12/03 - 13:11:23" level=debug msg="Init App Status Engine as memory"
time="2019/12/03 - 13:11:23" level=debug msg="worker number is 1, queue number is 8192"
time="2019/12/03 - 13:11:23" level=debug msg="gRPC server is disabled."
time="2019/12/03 - 13:11:23" level=debug msg="HTTPD server is running on 8088 port."
START RequestId: 577298fc-391b-45f8-8b71-0276ae6ef285 Version: $LATEST
time="2019/12/03 - 13:11:23" level=info msg="| header | POST /api/push ***.***.***.** application/x-www-form-urlencoded curl/7.64.0"
[GIN] 2019/12/03 - 13:11:23 | 200 | 19.856858ms | ***.***.***.** | POST /api/push
END RequestId: 577298fc-391b-45f8-8b71-0276ae6ef285
REPORT RequestId: 577298fc-391b-45f8-8b71-0276ae6ef285 Duration: 22.44 ms Billed Duration: 100 ms Memory Size: 256 MB Max Memory Used: 37 MB Init Duration: 165.13 ms
time="2019/12/03 - 13:22:23" level=debug msg="Start push notification for iOS"
```
```
time="2019/12/03 - 13:09:16" level=debug msg="Init App Status Engine as memory"
time="2019/12/03 - 13:09:16" level=debug msg="worker number is 1, queue number is 8192"
time="2019/12/03 - 13:09:16" level=debug msg="gRPC server is disabled."
time="2019/12/03 - 13:09:16" level=debug msg="HTTPD server is running on 8088 port."
START RequestId: ec315752-52be-44d3-9449-370e0c82c5bd Version: $LATEST
time="2019/12/03 - 13:09:16" level=info msg="| header | POST /api/push ***.***.***.** application/x-www-form-urlencoded curl/7.64.0"
[GIN] 2019/12/03 - 13:09:16 | 200 | 21.243728ms | ***.***.***.** | POST /api/push
END RequestId: ec315752-52be-44d3-9449-370e0c82c5bd
REPORT RequestId: ec315752-52be-44d3-9449-370e0c82c5bd Duration: 41.48 ms Billed Duration: 100 ms Memory Size: 256 MB Max Memory Used: 37 MB Init Duration: 160.80 ms
START RequestId: 2d4bef34-c9d1-4df0-a991-f8c490c9f49b Version: $LATEST
time="2019/12/03 - 13:09:16" level=debug msg="Start push notification for Android"
END RequestId: 2d4bef34-c9d1-4df0-a991-f8c490c9f49b
REPORT RequestId: 2d4bef34-c9d1-4df0-a991-f8c490c9f49b Duration: 1.12 ms Billed Duration: 100 ms Memory Size: 256 MB Max Memory Used: 38 MB
START RequestId: c6e28c9c-0b66-41cb-a187-6942dba42931 Version: $LATEST
time="2019/12/03 - 13:09:23" level=info msg="| header | POST /api/push ***.***.***.** application/x-www-form-urlencoded curl/7.64.0"
[GIN] 2019/12/03 - 13:09:23 | 200 | 136.232µs | ***.***.***.** | POST /api/push
time="2019/12/03 - 13:10:49" level=error msg="FCM server send message error: Post https://fcm.googleapis.com/fcm/send: context deadline exceeded"
time="2019/12/03 - 13:10:49" level=debug msg="Start push notification for Android"
time="2019/12/03 - 13:10:49" level=info msg="| header | POST /api/push ***.***.***.** application/x-www-form-urlencoded curl/7.64.0"
[GIN] 2019/12/03 - 13:10:49 | 200 | 137.488µs | ***.***.***.** | POST /api/push
END RequestId: c6e28c9c-0b66-41cb-a187-6942dba42931
REPORT RequestId: c6e28c9c-0b66-41cb-a187-6942dba42931 Duration: 1.43 ms Billed Duration: 100 ms Memory Size: 256 MB Max Memory Used: 38 MB
```

Config file ( GET from https://*************.execute-api.us-west-1.amazonaws.com/prod/api/config)

```
core:
enabled: true
address: ""
port: "8088"
max_notification: 100
worker_num: 2
queue_num: 8192
mode: release
sync: false
ssl: false
cert_path: cert.pem
key_path: key.pem
cert_base64: ""
key_base64: ""
http_proxy: ""
feedback_hook_url: ""
pid:
enabled: false
path: gorush.pid
override: true
auto_tls:
enabled: false
folder: .cache
host: ""
api:
push_uri: /api/push
stat_go_uri: /api/stat/go
stat_app_uri: /api/stat/app
config_uri: /api/config
sys_stat_uri: /sys/stats
metric_uri: /metrics
health_uri: /healthz
android:
enabled: true
apikey: **************************************************************_vGI
max_retry: 0
ios:
enabled: false
key_path: key.pem
key_base64: ""
key_type: pem
password: ""
production: false
max_retry: 0
key_id: ""
team_id: ""
log:
format: string
access_log: stdout
access_level: debug
error_log: stderr
error_level: error
hide_token: true
stat:
engine: memory
redis:
addr: localhost:6379
password: ""
db: 0
boltdb:
path: bolt.db
bucket: gorush
buntdb:
path: bunt.db
leveldb:
path: level.db
grpc:
enabled: false
port: "9000"
```

Start with the AWS Lambda and API Gateway setup described in the report, then trace the /api/push entry point and the FCM request that ends with context deadline exceeded. Reproduce the Android push failure in the reported configuration; done means the push request completes successfully without the timeout.

Written by the indexing model from the issue text.