@Nullable
    default Boolean allowSemicolonInPathComponent() {
        return null;
    }
Returns whether to allow a semicolon ({@code ;}) in a request path component on the server-side.
If disabled, the substring from the semicolon to before the next slash, commonly referred to as
matrix variables, is removed. For example, {@code /foo;a=b/bar} will be converted to {@code /foo/bar}.
Also, an exception is raised if a semicolon is used for binding a service. For example, the following
code raises an exception:
<pre>{@code
Server server =
   Server.builder()
     .service("/foo;bar", ...)
     .build();
}</pre>
Note that this flag has no effect on the client-side.

<p>This flag is disabled by default. Specify the
{@code -Dcom.linecorp.armeria.allowSemicolonInPathComponent=true} JVM option to enable it.
core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java