Update Connection.php

[andiechang]

What does this PR do?

fix this issue: swoft-cloud/swoft#1365

Does this fix any issues or need any specific reviewers?

Fixes: swoft-cloud/swoft#1365
Reviewers: @inhere @sakuraovq

Motivation

question:
生產環境大量連線時，會出現 MySQL server has gone away。

MySQL setting:
interactive_timeout = 60
wait_timeout = 60

swoft:
db 使用讀寫分離設定
db.pool 設定：

'db.pool' => [
        'class' => Pool: :class,
        'database' => bean('db'),
        'minActive' => 10,
        'maxActive' => 30,
        'maxWait' => 15,
        'maxWaitTime' => 15,
        'maxIdleTime' => 30,
    ]

More

• Added/updated tests
• Added/updated documentation new or old

Additional Notes

[inhere]

你这代码格式变动太大了吧 :(