Fixes duplicated messages with fifo and dispose #1659

Job	Run time
Lint	35s
Coverage (ubuntu-latest)	45s
Python Tests (ubuntu-latest, 3.8, pytest)	46s
Create VSIX (windows-latest, x86_64-pc-windows-msvc, win32-x64)	6m 23s
Python Tests (ubuntu-latest, 3.8, pytest@pre-release)	46s
Create VSIX (windows-latest, aarch64-pc-windows-msvc, win32-arm64)	6m 14s
Native Tests (ubuntu-latest)	36s
Python Tests (ubuntu-latest, 3.8, pytest==6.2.0)	49s
Create VSIX (ubuntu-latest, x86_64-unknown-linux-musl, linux-x64)	3m 13s
Tests (ubuntu-latest, 3.x, ts-unit)	36s
Native Tests (windows-latest)	1m 32s
Create VSIX (ubuntu-latest, x86_64-unknown-linux-musl, alpine-x64)	3m 20s
Python Tests (ubuntu-latest, 3.x, pytest)	53s
Tests (ubuntu-latest, 3.x, venv)	36s
Python Tests (ubuntu-latest, 3.x, pytest@pre-release)	56s
Tests (ubuntu-latest, 3.x, single-workspace)	43s
Check Python types	38s
Python Tests (ubuntu-latest, 3.x, pytest==6.2.0)	51s
Tests (ubuntu-latest, 3.x, debugger)	35s
Python Tests (windows-latest, 3.8, pytest)	2m 53s
Tests (ubuntu-latest, 3.x, functional)	42s
Python Tests (windows-latest, 3.8, pytest@pre-release)	2m 42s
Tests (windows-latest, 3.x, ts-unit)	1m 38s
Python Tests (windows-latest, 3.8, pytest==6.2.0)	2m 20s
Tests (windows-latest, 3.x, venv)	1m 21s
Python Tests (windows-latest, 3.x, pytest)	2m 48s
Tests (windows-latest, 3.x, single-workspace)	1m 9s
Python Tests (windows-latest, 3.x, pytest@pre-release)	2m 16s
Tests (windows-latest, 3.x, debugger)	1m 34s
Python Tests (windows-latest, 3.x, pytest==6.2.0)	2m 25s
Tests (windows-latest, 3.x, functional)	1m 29s
Smoke tests	0s
	54m 4s

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