Disconnection from postgres-compatible google cloud AlloyDB instance hangs

• asyncpg version: 0.26.0
• PostgreSQL version: Google AlloyDB, postgres 14.4 compatible
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: I cannot reproduce the issue on a local postgres, no.
• Python version: 3.10
• Platform: Macos
• Do you use pgbouncer?: No
• Did you install asyncpg with pip?: Yes
• If you built asyncpg locally, which version of Cython did you use?: NA
• Can the issue be reproduced under both asyncio and
  uvloop?: I have not tried to reproduce under uvloop

I am connecting to an AlloyDB instance on Google Cloud (currently, these are available for free testing). I can connect and queries run as expected. However, connection.disconnect() hangs. I cannot reproduce this behavior locally; disconnection happens as expected. Synchronous database work with psycopg2, for example, works as expected.

This code reproduces the behavior I am seeing (running through the alloydb-auth-proxy as is required):

import asyncpg
conn = await asyncpg.connect(ALLOYDB_URI)
conn.disconnect() # hangs

I'll put in a ticket with Google as well if nothing obvious turns up here.

从提供的 AlloyDB-auth-proxy 复现中的 connection.disconnect() 调用开始，针对报告的 Google Cloud AlloyDB 设置运行它。将其行为与本地 PostgreSQL 安装和现有的 psycopg2 行为进行比较；完成标准是确定挂起的原因，并确保 asyncpg 在此设置下干净地断开连接。