public ExportGroupBuilder requestHeader(CharSequence headerName, String alias) {
        requireNonNull(headerName, "headerName");
        requireNonNull(alias, "alias");
        reqHeaders.add(new ExportEntry<>(toHeaderName(headerName), alias));
        return this;
    }
Adds the specified HTTP request header name to the export list.
The specified {@code alias} is used for the export key.
core/src/main/java/com/linecorp/armeria/common/logging/ExportGroupBuilder.java