Add a lot of documentation

error_response.go

@@ -28,8 +28,11 @@ type ErrorResponse struct {
 	UnknownFields map[byte]string
 }
 
+// Backend identifies this message as sendable by the PostgreSQL backend.
 func (*ErrorResponse) Backend() {}
 
+// Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message
+// type identifier and 4 byte message length.
 func (dst *ErrorResponse) Decode(src []byte) error {
 	*dst = ErrorResponse{}
 
@@ -103,6 +106,7 @@ func (dst *ErrorResponse) Decode(src []byte) error {
 	return nil
 }
 
+// Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
 func (src *ErrorResponse) Encode(dst []byte) []byte {
 	return append(dst, src.marshalBinary('E')...)
 }