6.2.1

Changes Between 6.1.0 and 6.2.1

This releases primarily focuses on efficiency improvements and addressing
bugs introduced in 6.x releases.

A full list of changes can be found in the GitHub milestone: 6.2.0.

Key highlights include:

• Concurrent publishing on a shared channel is now safer. We still recommend avoiding it when possible
  but safety properties have been improved by changing how outgoing frame sequences are serialised.

  Contributed by @bollhals.

  GitHub issue: #878

• Batch publishing using System.ReadOnlyMemory<byte> payloads instead of byte arrays.

  Contributed by @danielmarbach.

  GitHub issue: #865, #892