Add a lot of documentation

parse.go

@@ -14,8 +14,11 @@ type Parse struct {
 	ParameterOIDs []uint32
 }
 
+// Frontend identifies this message as sendable by a PostgreSQL frontend.
 func (*Parse) Frontend() {}
 
+// 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 *Parse) Decode(src []byte) error {
 	*dst = Parse{}
 
@@ -48,6 +51,7 @@ func (dst *Parse) 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 *Parse) Encode(dst []byte) []byte {
 	dst = append(dst, 'P')
 	sp := len(dst)
@@ -68,6 +72,7 @@ func (src *Parse) Encode(dst []byte) []byte {
 	return dst
 }
 
+// MarshalJSON implements encoding/json.Marshaler.
 func (src *Parse) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Type          string