TODO
Length in UTF-8 code units (bytes) of the span the message corresponds to.
Line number where the message is attached, starting at 1.
Offset in UTF-8 code units (bytes) from the beginning of the line, starting at 1.
A LocalizableHumanReadableMessageString.
Offset in UTF-8 code units (bytes) from the beginning of the shader code, starting at 0.
Severity level of the message.