feat: Add estimated_amount_in to Swap. Add SwapBuilder

Use SwapBuilder everywhere inside crate
Integration tests will be done later

--- don't change below this line ---
ENG-4696 Took 1 hour 56 minutes

Took 4 minutes

src/encoding/models.rs

@@ -89,6 +89,9 @@ pub struct Swap<'a> {
     /// Optional protocol state used to perform the swap.
     #[serde(skip)]
     pub protocol_state: Option<&'a dyn ProtocolSim>,
+    /// Optional estimated amount in for this Swap. This is necessary for RFQ protocols. This value
+    /// is used to request the quote
+    pub estimated_amount_in: Option<BigUint>,
 }
 
 impl<'a> Swap<'a> {
@@ -99,8 +102,17 @@ impl<'a> Swap<'a> {
         split: f64,
         user_data: Option<Bytes>,
         protocol_state: Option<&'a dyn ProtocolSim>,
+        estimated_amount_in: Option<BigUint>,
     ) -> Self {
-        Self { component: component.into(), token_in, token_out, split, user_data, protocol_state }
+        Self {
+            component: component.into(),
+            token_in,
+            token_out,
+            split,
+            user_data,
+            protocol_state,
+            estimated_amount_in,
+        }
     }
 }
 
@@ -115,6 +127,66 @@ impl<'a> PartialEq for Swap<'a> {
     }
 }
 
+pub struct SwapBuilder<'a> {
+    component: ProtocolComponent,
+    token_in: Bytes,
+    token_out: Bytes,
+    split: f64,
+    user_data: Option<Bytes>,
+    protocol_state: Option<&'a dyn ProtocolSim>,
+    estimated_amount_in: Option<BigUint>,
+}
+
+impl<'a> SwapBuilder<'a> {
+    pub fn new<T: Into<ProtocolComponent>>(
+        component: T,
+        token_in: Bytes,
+        token_out: Bytes,
+    ) -> Self {
+        Self {
+            component: component.into(),
+            token_in,
+            token_out,
+            split: 0.0,
+            user_data: None,
+            protocol_state: None,
+            estimated_amount_in: None,
+        }
+    }
+
+    pub fn split(mut self, split: f64) -> Self {
+        self.split = split;
+        self
+    }
+
+    pub fn user_data(mut self, user_data: Bytes) -> Self {
+        self.user_data = Some(user_data);
+        self
+    }
+
+    pub fn protocol_state(mut self, protocol_state: &'a dyn ProtocolSim) -> Self {
+        self.protocol_state = Some(protocol_state);
+        self
+    }
+
+    pub fn estimated_amount_in(mut self, estimated_amount_in: BigUint) -> Self {
+        self.estimated_amount_in = Some(estimated_amount_in);
+        self
+    }
+
+    pub fn build(self) -> Swap<'a> {
+        Swap {
+            component: self.component,
+            token_in: self.token_in,
+            token_out: self.token_out,
+            split: self.split,
+            user_data: self.user_data,
+            protocol_state: self.protocol_state,
+            estimated_amount_in: self.estimated_amount_in,
+        }
+    }
+}
+
 /// Represents a transaction to be executed.
 ///
 /// # Fields
@@ -262,6 +334,7 @@ mod tests {
             0.5,
             user_data.clone(),
             None,
+            None,
         );
         assert_eq!(swap.token_in, Bytes::from("0x12"));
         assert_eq!(swap.token_out, Bytes::from("0x34"));