public Builder packageName(final String packageName)
        {
            this.packageName = packageName;
            return this;
        }
Package name for the Token, default is null. Use for BEGIN_MESSAGE tokens for types that require an explicit
package.

@param packageName for the Token.
@return this for a fluent API.
sbe-tool/src/main/java/uk/co/real_logic/sbe/ir/Token.java