Fix busy loop

• Fix a busy loop due to WANT_WRITE flag for a closed stream.

Fix handshake padding, packet split

• Properly pad handshake packet to minimum 1200 bytes.
• Fix a corner case in packet split

Fix bpq_count

• Fix bpq_count (issue #504)

Fix RETIRE_CONNECTION_ID frame abuse

• Fix RETIRE_CONNECTION_ID frame abuse.
• Fix some assert failures.

Fix 0-RTT packet validation, update docker build

• Fix overly strict 0-RTT packet DCID validation.
• Update docker build.

Fix ACK and CONNECTION_CLOSE

• Fix ACK handling.
• Do not apply congestion control to CONNECTION_CLOSE frame.

More STREAM_BLOCKED fixes

• Fix CPU spinning due to sending STREAM_BLOCKED frame.

Fix sending STREAM_BLOCKED frame

• Address high CPU usage related to sending STREAM_BLOCKED frame

Fix DCID validation and CPU spin

• Fix DCID validation.
• Fix CPU spinning due to pending STREAM_BLOCKED frame.

Fix session resumption

• Fix session resumption bug introduced in 4.0.2.