aeron-client/src/main/java/io/aeron/command/PublicationMessageFlyweight.java
public PublicationMessageFlyweight channel(final String channel)
    {
        lengthOfChannel = buffer.putStringAscii(offset + CHANNEL_OFFSET, channel);

        return this;
    }
public PublicationMessageFlyweight channel(final String channel)
    {
        lengthOfChannel = buffer.putStringAscii(offset + CHANNEL_OFFSET, channel);

        return this;
    }
Set the channel field in ASCII

@param channel field value
@return flyweight