static void populateConnectionAttributes(final Map<AttributeKey<?>, Object> attributes,
    final AsyncConnectionImpl conn) {
    final Supplier<String> connStringSupplier =
      () -> conn.getConnectionRegistry().getConnectionString();
    populateConnectionAttributes(attributes, connStringSupplier, conn::getUser);
  }
Static utility method that performs the primary logic of this builder. It is visible to other
classes in this package so that other builders can use this functionality as a mix-in.
@param attributes the attributes map to be populated.
@param conn       the source of connection attribute values.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/trace/ConnectionSpanBuilder.java