GH-370 Also compare file keys in ModifiableFileWatcher.
GH-371 Fix channel pool in SftpFileSystem.
SSHD-1310 SftpFileSystem: do not close user session.
SSHD-1327 ChannelAsyncOutputStream: remove write future when done.
As part of the fix for GH-371 the channel pool in SftpFileSystem was rewritten completely. Previous code also used ThreadLocals to store SftpClients, which could cause memory leaks.
These ThreadLocals have been removed, and the channel pool has been rewritten to function similar to a Java ThreadPool: the pool has a maximum size; it has an expiration duration after which an idle channel is removed and closed, and it has a “core size” of channels to keep even if they are idle. If a channel is closed for any reason it is evicted from the pool.
Properties to configure these pool parameters have been added to SftpModuleProperties.