Add basic transaction/block code to Tributary

coordinator/tributary/src/lib.rs

@@ -1 +1,23 @@
+use std::io;
 
+mod merkle;
+pub(crate) use merkle::*;
+
+mod transaction;
+pub use transaction::*;
+
+mod block;
+pub use block::*;
+
+/// An item which can be read and written.
+pub trait ReadWrite: Sized {
+  fn read<R: io::Read>(reader: &mut R) -> io::Result<Self>;
+  fn write<W: io::Write>(&self, writer: &mut W) -> io::Result<()>;
+
+  fn serialize(&self) -> Vec<u8> {
+    // BlockHeader is 64 bytes and likely the smallest item in this system
+    let mut buf = Vec::with_capacity(64);
+    self.write(&mut buf).unwrap();
+    buf
+  }
+}