The error code is a string that uniquely identifies an error condition. It is
meant to be read and understood by programs that detect and handle errors by
type. Many error codes are common across SOAP and REST APIs, but some are
API-specific. For example, NoSuchKey is universal, but UnexpectedContent can
occur only in response to an invalid REST request. In all cases, SOAP fault
codes carry a prefix as indicated in the table of error codes, so that a
NoSuchKey error is actually returned in SOAP as Client.NoSuchKey.